SecProbe.io

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 Branden Berns Partner
 T: +1 415.393.4631 BBerns@gibsondunn.com
 July 23, 2025 VIA
ELECTRONIC MAIL AND EDGAR FILING United States Securities and Exchange Commission
 Division of Corporation Finance Office of Mergers and
Acquisitions 100 F Street NE Washington, D.C. 20549
 Attention: Mr. Blake Grady XOMA Royalty Corporation
 Turnstone Biologics Corp. Schedule TO-T Filed July 11, 2025 Filed by XOMA Royalty Corporation
 File No. 005-94123
 Dear Mr. Grady: On behalf of XOMA Royalty
Corporation (the “ Purchaser ”), please find responses to comments received from the Staff of the Division of Corporation Finance (the “ Staff ”) of the Securities and Exchange Commission (the
“ Commission ”) by letter dated July 18, 2025 (“ Letter ”), with respect to the Purchaser’s Schedule TO-T filed on July 11, 2025 (the “ Schedule
TO ”) and the Offer to Purchase, dated July 11, 2025 (the “ Offer to Purchase ” and, together with the Schedule TO, the “ Tender Offer Materials ”). Concurrently with delivery of this letter, the Purchaser
filed updated Tender Offer Materials (the “ Revised Tender Offer Materials ”), including a Schedule TO-T/A and revised Offer to Purchase (the “ Revised Offer to Purchase ”), which
reflect, among other things, revisions to address the Staff’s comments. For your convenience, we have restated below in bold each
comment from the Letter and supplied our responses immediately thereafter. Unless otherwise specified, all references to page numbers and captions correspond to the Offer to Purchase and all capitalized terms used but not defined herein have the
same meaning as in the Tender Offer Materials. General

 1.
 We note that the principal business of Purchaser, as described on page
 A-1, is solely “to consummate the Offer and effect the Merger pursuant to the Merger Agreement, and to perform its obligations under the CVR Agreement.” However, your Schedule TO states that the
principal business of Purchaser is “to engage in any lawful act or activity for which corporations may be organized under the Nevada Revised Statutes,” and Purchaser’s website states that “XOMA is a biotechnology royalty
aggregator … with more than 70 assets.” Please revise to address these apparent discrepancies. Refer to Item 1003(b) of Regulation M-A.
 Gibson, Dunn & Crutcher LLP
 One Embarcadero Center Suite 2600 | San Francisco, CA 94111-3715 | T: 415.393.8200 | F: 415.393.8306 | gibsondunn.com

 July 23, 2025
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 Response : In response to the Staff’s comment, Purchaser has revised the
disclosure in the Revised Tender Offer Materials to clarify that Purchaser is a Nevada corporation whose primary business is as a biotech royalty aggregator with a sizable portfolio of economic rights to future potential milestone and royalty
payments associated with partnered commercial and pre-commercial therapeutic drug candidates (see page 2 of the Schedule TO-T/A).

 2.
 Disclosure on page A-1 indicates that “Mr. Burns joined
Purchaser in August 2006.” However, based on disclosure in Item 3 of your Schedule TO, it appears that Purchaser was formed in 2011. Please revise or advise.
 Response : In response to the Staff’s comment, Purchaser has revised the disclosure in the Revised Tender Offer Materials to clarify
that Purchaser was incorporated in Delaware in 1981 and redomiciled as a Bermuda-exempted company in December 1998. Effective December 31, 2011, Purchaser redomiciled from Bermuda back to Delaware. Purchaser subsequently reincorporated in
Nevada on May 30, 2025 (see page 2 of the Schedule TO-T/A).

 3.
 Please disclose the information required by Item 1008(a) and (b) of Regulation M-A. Response: In response to the Staff’s comment, Purchaser has
revised the disclosure in the Revised Tender Offer Materials to include the following information (see page 34 of the Revised Offer to Purchase):
 “As of July 23, 2025, neither Purchaser nor any of Purchaser’s executive officers and directors beneficially owned any Shares
of Turnstone. No transactions with respect to the Shares have been effected by Purchaser, or, to Purchaser’s knowledge after making reasonable inquiry, any of the directors, executive officers or affiliates of Purchaser, during the 60 days
prior to the date of this Offer to Purchaser.”

 4.
 Refer to the first bullet point under the caption “What Is the CVR and How Does It Work?” on page
2. Please provide illustrative disclosure, in plain English, showing how the CVR Proceeds will be calculated, including how Net Cash Excess and Net Cash Shortfall will be calculated. Refer to Item 1001 of Regulation
 M-A and to Item 1004(a)(1)(ii) of Regulation M-A.
 Response: In response to the Staff’s comment, Purchaser has revised the first bullet point and included a new second bullet under
the caption “What Is the CVR and How Does It Work” in the Revised Tender Offer Materials with the following language (see page 3 of the Revised Offer to Purchase):

 •

 “At or prior to the Offer Closing Time, Purchaser, Merger Sub, the rights agent (the “ Rights
Agent ”) and the representative of the holders of the CVRs (the “ Representative ”) will enter into the CVR Agreement, governing the terms of the CVRs. Each CVR will represent a

 July 23, 2025
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contractual right to receive contingent cash payments equal to a pro rata share of: (i)(a) the net tax receivables from Canadian federal and territory/provincial tax authorities and/or
Québec Scientific Research and Experimental Development (“SR&ED”) tax credit program as tax refunds up to $850,000 (excluding the $55,610 Québec SR&ED amount that has been scheduled on Schedule 1.01 of the Merger
Agreement) and (b) the payments received from the landlord under the Sublease, dated November 16, 2022, between Turnstone and Medivis, Inc., as a return of security deposit up to $260,000 ((a) and (b) together, the “ Legacy
Receivable Amount ”), plus (ii) Net Cash Excess (as defined below), if any, and minus (iii) Net Cash Shortfall (as defined below), if any. “ Net Cash Excess ” means if Final Net Cash is greater than Closing Net Cash
(each as defined in the Merger Agreement and calculated in accordance with Section 2.01(c) of the Merger Agreement), then the amount equal to (a) Final Net Cash, minus (b) Closing Net Cash. “ Net Cash Shortfall ” means
if Final Net Cash is less than Closing Net Cash, then the amount equal to (a) Closing Net Cash, minus (b) Final Net Cash.

 •

 For illustrative purposes only, assuming that: (a) Turnstone receives $510,000 in tax refunds from Canadian
tax authorities (i.e., 60% of the maximum refund amount), and $156,000 from Medivis, Inc. as a return of the security deposit under the Sublease Agreement (also 60% of the maximum amount), and (b) Final Net Cash is $3,000,000 and Closing Net
Cash is $3,000,000, such that there is no Net Cash Excess or Net Cash Shortfall, then the aggregate amount payable under the CVRs would be $666,000 or approximately $0.03 per CVR (based on (i) 23,140,691 Shares issued and outstanding, and (ii) 1,135
Shares underlying Turnstone RSUs).”

 5.
 On page 3, disclosure indicates that the “offeror estimates that the amount that will be payable (on a pre-tax basis) under the CVRs will be approximately $0.03 per CVR.” Revise the Offer to Purchase to explain the basis for the offeror’s belief with respect to the CVRs.
 Response: In response to the Staff’s comment, Purchaser has revised the disclosure in the Revised Tender Offer Materials to explain
the basis for the offeror’s belief with respect to the CVRs (see pages 2 and 3 of the Revised Offer to Purchase): “We cannot
predict whether any CVR Proceeds will be received or, if any CVR Proceeds are received, the amount or timing of any such receipt. In connection with the Offer, the offeror did not engage any independent valuation firm to conduct an analysis of the
potential value of the CVR Proceeds or receive any material non-public information assessing the value of the CVR Proceeds. The offeror is relying on Turnstone’s estimate of the CVR Proceeds that would be
payable. Accordingly, in making a decision to tender your Shares in the Offer, you should understand that there can be no assurance whether there will be any payments under the CVR Agreement or with respect to the amount and timing of such
payments (if any). You should also understand that, as discussed below, it is estimated that the amount that will be payable under the CVRs will be approximately $0.03 per CVR. Turnstone has determined that the maximum payout for the CVR is
estimated to be up to $0.05 per CVR, assuming payment in full of the tax refund and lease deposit and no positive or negative adjustment to the CVR Proceeds because of a Net Cash Excess or a Net Cash Shortfall, respectively. After accounting for the
likelihood of different payment scenarios for the tax refund and lease deposit, Turnstone has applied a 40% discount for the tax refund and lease deposit and has assumed no adjustments for net cash calculations under the CVR Agreement. Accordingly,
the probability-weighted estimate of the amount payable is $0.03 per CVR.

 July 23, 2025
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 4

 In determining the probability-weighted estimated payout, we note that there can be no
assurance: (i) that Turnstone will receive the tax receivables and/or the return of a lease security deposit prior to the expiration of the CVRs necessary for payment pursuant to the CVRs, (ii) that there will be any positive or negative
adjustments based on the post-closing calculation of Closing Net Cash or (iii) regarding the exact amount of CVR Proceeds or the timing of any such payment, if any. Neither the Merger Agreement nor the CVR Agreement requires Purchaser to use any
efforts in connection with the CVR Proceeds. The discount reflects Turnstone’s assessment of the fair value of the CVRs, taking into account the contingent nature of the payment, the absence of industry benchmarks for similar instruments, and
the inherent uncertainty regarding the receipt of payments for the tax refunds or security deposit. This estimate is subject to change and should not be construed as a prediction or guarantee of actual payments under the CVRs. If any CVR Proceeds
are received after one year following the date of the closing of the Merger, holders of the CVRs will not receive any payment pursuant to the CVR Agreement. Accordingly, in deciding whether to tender your Shares into the Offer, you should understand
that it is possible that no payment will be made pursuant to the CVRs.” * * * * *
 If you have any further questions or comments, or if you require any additional information, please contact Branden Berns of Gibson,
Dunn & Crutcher LLP, by telephone at (415) 393-4631. Thank you for your assistance.

 Very truly yours,
 Owen Hughes

 By:

 /s/ Owen Hughes

 Owen Hughes
 Via E-mail:

 cc:
 Ryan A. Murr, Gibson, Dunn & Crutcher LLP
 Branden C. Berns, Gibson, Dunn & Crutcher LLP
 Melanie E. Neary, Gibson, Dunn & Crutcher LLP
 Sammy Farah, Turnstone Biologics Corp.

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 June 13, 2024

VIA EDGAR

 United States Securities and Exchange
Commission

 Division of Corporation Finance

 Office of Life
Sciences

 100 F Street, N.E.

 Washington, D.C. 20549

Attn: Jason Drory and Alan Campbell

Re:
 XOMA Corporation

Registration Statement on Form S-4 filed on March 8, 2024 (File
No. 333-277812)

 To Whom it May Concern:

Pursuant to Rule 461 promulgated under the Securities Act of 1933, as amended (the “Act”), XOMA Corporation, a Delaware corporation
(the “Company”), hereby respectfully requests that the effective time of the above referenced Registration Statement on Form S-4 filed by the Company be accelerated to 4:00 p.m., Eastern Time, on
June 17, 2024 or as soon thereafter as practicable, unless we or our outside counsel, Gibson, Dunn & Crutcher LLP, request by telephone that such Registration Statement be declared effective at some other time. In making this
acceleration request, the Company acknowledges that it is aware of its obligations under the Act.

 Once the Registration Statement is
effective, please orally confirm the event with our counsel, Gibson, Dunn & Crutcher LLP by calling Ryan A. Murr at (415) 393-8373.

Very truly yours,

XOMA Corporation

By:

/s/ Owen Hughes

Name:

Owen Hughes

Title:

Chief Executive Officer

cc:
 Thomas Burns, XOMA Corporation

Christopher Baldwin, XOMA Corporation

Branden Berns, Gibson, Dunn & Crutcher LLP

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CORRESP

 June 13, 2024

VIA EDGAR

 United States Securities and Exchange
Commission

 Division of Corporation Finance

 Office of Life
Sciences

 100 F Street, N.E.

 Washington, D.C. 20549

Attn: Jason Drory and Alan Campbell

Re:
 XOMA Corporation

 
 Registration Statement on Form S-3 filed on March 8, 2024 (File
No. 333-277794)

 To Whom it May Concern:

Pursuant to Rule 461 promulgated under the Securities Act of 1933, as amended (the “Act”), XOMA Corporation, a Delaware corporation
(the “Company”), hereby respectfully requests that the effective time of the above referenced Registration Statement on Form S-3 filed by the Company be accelerated to 4:00 p.m., Eastern Time, on
June 17, 2024 or as soon thereafter as practicable, unless we or our outside counsel, Gibson, Dunn & Crutcher LLP, request by telephone that such Registration Statement be declared effective at some other time. In making this
acceleration request, the Company acknowledges that it is aware of its obligations under the Act.

 Once the Registration Statement is
effective, please orally confirm the event with our counsel, Gibson, Dunn & Crutcher LLP by calling Ryan A. Murr at (415) 393-8373.

Very truly yours,

XOMA Corporation

By:

/s/ Owen Hughes

 Name:

 Owen Hughes

 Title:

 Chief Executive Officer

cc:
 Thomas Burns, XOMA Corporation

 
 Christopher Baldwin, XOMA Corporation

 
 Branden Berns, Gibson, Dunn & Crutcher LLP

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 Gibson, Dunn & Crutcher LLP

One Embarcadero Center, Suite 2600

 San Francisco, CA
94111-3715

 Tel 415.393.8200

 gibsondunn.com

 Privileged and Confidential

May 10, 2024

 EDGAR CORRESPONDENCE

U.S. Securities and Exchange Commission

 Division of Corporation
Finance

 Office of Life Sciences

 100 F Street, N.E.

Washington, D.C. 20549

 Attn: Jason Drory and Alan Campbell

Re:
 XOMA Corporation:

Registration Statement on Form S-3 filed on March 8, 2024 (File No.
333-277794)

 Registration Statement on Form S-4 filed on
March 8, 2024 (File No. 333-277812)

 Ladies and Gentlemen:

On behalf of XOMA Corporation (“XOMA” or the “Company”), this letter responds to the comments of the staff of
the U.S. Securities and Exchange Commission (the “Staff”) contained in your letter, dated May 2, 2024 (the “Comment Letter”), regarding the above-referenced Registration Statement on Form S-3 (File No. 333-277794) and Registration Statement on Form S-4 (File
No. 333-277812) (together, the “Registration Statements”) requesting additional information with respect the Company’s response to the Staff’s prior comment letter, dated
April 3, 2024, regarding the Registration Statements (the “4/03 Comment Letter”).

 The Staff’s comments are set
forth below followed by the Company’s responses. For ease of reference, the headings and numbered paragraphs below correspond to the Staff’s comments. The Company’s responses are set forth in ordinary type below the Staff’s
comments, which are set forth in bold type. References are made to the Company’s Form 10-K for the fiscal year ended December 31, 2023, filed on March 8, 2024 (File No. 001-39801). Capitalized terms not otherwise defined herein have the meanings specified in the Company’s response to the 4/03 Comment Letter, dated April 17, 2024 (the “4/17 Response
Letter”).

 Abu Dhabi • Beijing
• Brussels • Century City • Dallas • Denver • Dubai • Frankfurt • Hong Kong • Houston • London • Los Angeles

Munich • New York • Orange County • Palo Alto • Paris • Riyadh • San Francisco • Singapore • Washington,
D.C.

 U.S. Securities and Exchange Commission

May 10, 2024

1.
 We note in your response to prior comment 2 included in our April 3, 2024 letter that “[o]nce the
Specified Product has received FDA approval and is being marketed, the payments received by XOMA US in respect of the applicable Royalty Interest are typically calculated as a percentage of sales revenues generated by the Specified
Product….” (emphasis added). Please supplementally explain this reference to “typically,” including what constitutes the “typical” circumstances under which Royalty Interests are so calculated, their frequency and under
what circumstance and frequency Royalty Interests are calculated in an “atypical” manner.

 In the 4/17
Response Letter, the statement that “once a Specified Product has received FDA approval and is being marketed, the payments received by XOMA US in respect of the applicable Royalty Interest are typically calculated as a percentage of sales
revenues generated by the Specified Product” was qualified by the term “typically” to take into account the fact that even after XOMA US begins to receive payments based on Sales-Based Receivables (“Sales-Based Royalty
Payments”) under the applicable Royalty Interest, it may still be possible for the XOMA US to receive payments based on Development Milestone Receivables (“Development Milestone Payments”) under the Royalty Interest. This
can occur in either of two scenarios:

(i)
 The Specified Product receives regulatory approval in another jurisdiction, which can trigger a Development
Milestone Payment; or

(ii)
 The applicable Royalty Interest covers more than one Specified Product, and a second Specified Product achieves
a development milestone after the first Specified Product has already begun generating Sales-Based Royalty Payments.

 In either
scenario, it remains the case that all Sales-Based Royalty Payments generated by the Royalty Interests that XOMA acquires are calculated as a percentage of sales revenues generated by Specified Products. In addition, for the sake of clarity, the
Company also confirms that no Milestone Development Receivables attributed to a Royalty Interest are counted towards compliance with the 55% threshold applied in the Royalty Pharma no-action letter, regardless
of whether the Royalty Interest has begun generating Sales-Based Royalty Payments.

2.
 Please update the Company’s risk factor disclosure to specifically reference (i) the
Company’s reliance on the exemption at section 3(c)(5)(A) of the Investment Company Act of 1940 and (ii) the Company’s belief that it may properly rely on the Royalty Pharma staff letter and its intent to do so.

 The Company’s risk factor disclosure regarding its status under the 1940 Act will be modified as follows in
the Company’s next Quarterly Report on Form 10-Q:

 Our royalty aggregator strategy may require that we register with the SEC as
an “investment company” in accordance with the Investment Company Act of 1940.

 2

 U.S. Securities and Exchange Commission

May 10, 2024

 The rules and interpretations of the SEC and the courts, relating to the
definition of “investment company” are very complex. We do not believe we are an “investment company” under applicable SEC rules, and we currently intend to conduct our operations so as not to be considered an “investment
company.” In particular, on an unconsolidated basis, we believe that less than 40% of our total assets (less any cash items or holdings in U.S. Government securities) currently consist of holdings in “investment securities.” This
conclusion is largely dependent on our analysis that XOMA (US) LLC, our primary subsidiary, is not an investment company in reliance on the exclusion from the definition of an investment company provided in Section 3(c)(5)(A) of the ‘40
Act, as interpreted by the Staff of the SEC in a no-action letter issued to Royalty Pharma on August 13, 2010. Nevertheless, we can provide no assurance that the SEC will not take the position that the
Company is required to register under the ‘40 Act and comply with the ‘40 Act’s registration and reporting requirements, capital structure requirements, affiliate transaction restrictions, conflict of interest rules, requirements for
disinterested directors, and other substantive provisions. We monitor our assets and income for compliance under the ‘40 Act and seek to conduct our business activities in a manner such that we do not fall within its definitions of
“investment company” or that we qualify under one of the exemptions or exclusions provided by the ‘40 Act and corresponding SEC regulations. However, if we were to be considered an “investment company” and become subject to
the restrictions of the ‘40 Act, those restrictions likely would require significant changes in the way we do business and add significant administrative costs and burdens to our operations. Additionally, we may need to take various actions
which we might otherwise not pursue in order to not come within scope of the ‘40 Act. These actions may include, among others, restructuring the Company and/or modifying our mixture of assets and income or a liquidation of certain of our
assets.

 *    *    *

Thank you for your consideration of this response. If you have any questions regarding the response set forth above, please do not hesitate to
call me at (415) 393-8373 or Branden C. Berns at (415) 393-4631.

Sincerely,

/s/ Ryan A. Murr

Ryan A. Murr

cc:
 Branden C. Berns, Gibson, Dunn & Crutcher LLP

Melanie Neary, Gibson, Dunn & Crutcher LLP

Owen Hughes, XOMA Corporation

Thomas Burns, XOMA Corporation

Christopher Baldwin, XOMA Corporation

 3

United States securities and exchange commission logo
May 2, 2024
Owen Hughes
Chief Executive Officer
XOMA Corporation
2200 Powell Street, Suite 310
Emeryville, CA 94608
Re:XOMA Corporation
Registration Statement on Form S-4
Response Dated April 17, 2024
File No. 333-277812
Dear Owen Hughes:
            We have reviewed your April 17, 2024 response to our comment letter and have the
following comments.
            Please respond to this letter by amending your registration statement and providing the
requested information. If you do not believe a comment applies to your facts and circumstances
or do not believe an amendment is appropriate, please tell us why in your response.
            After reviewing your response to this letter, we may have additional comments. Unless
we note otherwise, any references to prior comments are to comments in our April 3, 2024 letter.
Response Dated April 17, 2024
General
1.We note in your response to prior comment 2 included in our April 3, 2024 letter that
“[o]nce the Specified Product has received FDA approval and is being marketed, the
payments received by XOMA US in respect of the applicable Royalty Interest are
typically calculated as a percentage of sales revenues generated by the Specified
Product….” (emphasis added). Please supplementally explain this reference to “typically,”
including what constitutes the “typical” circumstances under which Royalty Interests are
so calculated, their frequency and under what circumstance and frequency Royalty
Interests are calculated in an “atypical” manner.
2.Please update the Company’s risk factor disclosure to specifically reference (i) the
Company’s reliance on the exemption at section 3(c)(5)(A) of the Investment Company
Act of 1940 and (ii) the Company’s belief that it may properly rely on the Royalty Pharma
staff letter and its intent to do so.

 FirstName LastNameOwen Hughes
 Comapany NameXOMA Corporation
 May 2, 2024 Page 2
 FirstName LastName
Owen Hughes
XOMA Corporation
May 2, 2024
Page 2
            Please contact Tamika Sheppard at 202-551-8346 or Alan Campbell at 202-551-4224
with any questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:       Branden C. Berns

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 Gibson, Dunn & Crutcher LLP

One Embarcadero Center, Suite 2600

San Francisco, CA 94111-3715

 Tel 415.393.8200

 gibsondunn.com

 April 17, 2024

 EDGAR
CORRESPONDENCE

 U.S. Securities and Exchange Commission

Division of Corporation Finance

 Office of Life Sciences

100 F Street, N.E.

 Washington, D.C. 20549

Attn: Jason Drory and Alan Campbell

 Re: XOMA Corporation:

Registration Statement on Form S-3 filed on March 8, 2024 (File No. 333-277794)

 Registration Statement on Form S-4 filed on
March 8, 2024 (File No. 333-277812)

 Ladies and Gentlemen:

On behalf of XOMA Corporation (“XOMA” or the “Company”), this letter responds to the comments of the staff
of the U.S. Securities and Exchange Commission (the “Staff”) contained in your letter, dated April 3, 2024 (the “Comment Letter”), regarding the above-referenced Registration Statement on Form S-3 (File No. 333-277794) and Registration Statement on Form S-4 (File
No. 333-277812) (together, the “Registration Statements”) requesting additional information with respect the Company’s response to the Staff’s prior comment letters dated
March 13, 2024 regarding the Registration Statements (the “Prior Comment Letters”).

 The Staff’s comments are
set forth below followed by the Company’s responses. For ease of reference, the headings and numbered paragraphs below correspond to the Staff’s comments. The Company’s responses are set forth in ordinary type below the Staff’s
comments, which are set forth in bold type. References are made to the Company’s Form 10-K for the fiscal year ended December 31, 2023, filed on March 8, 2024 (File No. 001-39801).

1.
 Please supplement your response to prior comment 1 by (i) identifying the approximate percentage of
your total assets (exclusive of Government securities and cash items) composed of your ownership interests in XOMA (US) LLC (“XOMA US”) and (ii) identifying the types of assets categorized as cash and cash equivalents (e.g., demand
deposits or registered money market funds) currently held by you, together with their approximate amounts.

 Abu Dhabi
• Beijing • Brussels • Century City • Dallas • Denver • Dubai • Frankfurt • Hong Kong • Houston • London • Los Angeles

Munich • New York • Orange County • Palo Alto • Paris • Riyadh • San Francisco • Singapore • Washington,
D.C.

 U.S. Securities and Exchange Commission

April 17, 2024

 As of December 31, 2023, on an unconsolidated basis, the approximate percentage of
XOMA’s total assets (exclusive of U.S. Government securities and cash items) that are composed of XOMA’s ownership interest in XOMA US was approximately 99.98%. As of such date, the types of assets characterized as cash and cash
equivalents on XOMA’s unconsolidated balance sheet consisted entirely of (i) cash held in demand deposit accounts at U.S. banks, and (ii) investments in money market funds registered as such under the Investment Company Act of 1940,
as amended (the “1940 Act”). As of December 31, 2023, the amount of cash held by XOMA in demand deposit accounts was approximately $0.4 million, and the amount of investments held by XOMA in money market funds was
approximately $152.7 million. XOMA does not hold any investments in U.S. Government securities.

2.
 Please supplement your response by providing your comprehensive, detailed legal analysis supporting your
contention that XOMA US is eligible for the 3(c)(5)(A) exclusion in view of the fact that Section 3(c)(5)(A) is available only where an acquired obligation represents part or all of the sales price of merchandise, insurance, and services. In
your response, please:

•

 Describe and discuss whether XOMA US’s royalty and commercial payment purchase agreements entitle XOMA US
to collect payments that are not directly based on the sales price of specific biopharmaceutical products, including for example in connection with (A) the meeting of certain regulatory, development, or other milestones, or
(B) biopharmaceutical products that either are not currently identified or were not currently identified at the time of entry into the agreement; and

•

 Describe and discuss whether any of the recorded values of the XOMA US’s royalty and commercial payment
receivables (both short and long-term) are attributable to such payment rights, and in what specific amounts.

 Each
of XOMA US’s royalty and commercial payment agreements (the “Royalty Interests”) relate to one or more specified biopharmaceutical products that were identified at the time of the acquisition of the applicable Royalty Interest
(each, a “Specified Product”). In some cases, at the time XOMA US acquires a Royalty Interest, the Specified Products to which the Royalty Interest relates are still in the process of undergoing clinical trials and/or obtaining
regulatory approval from the U.S. Food and Drug Administration (“FDA”) or a foreign equivalent. In such a case, the Royalty Interest may contemplate that payments will be made to XOMA US upon the successful completion of certain
development milestones, such as FDA approval, successful completion of Phase III clinical trials, or the completion of earlier-stage clinical trials (“Development Milestone Receivables”). Once the Specified Product has
received FDA approval and is being marketed, the payments received by XOMA US in respect of the applicable Royalty Interest are typically calculated as a percentage of sales revenues generated by the Specified Product (“Sales-Based Royalty
Receivables”). Under certain Royalty Interests, XOMA US may also be eligible to receive periodic lump-sum payments if the sales revenues generated by a Specified Product exceeds certain specified
thresholds (e.g., a $1.0 million lump-sum payment when sales reach $10.0 million, which is effectively a 10% royalty paid in lump-sum installments) (“Sales-Based Threshold
Receivables,” and, together with the Sales-Based Royalty Receivables, “Sales-Based Receivables”).

 2

 U.S. Securities and Exchange Commission

April 17, 2024

 As part of its due diligence process, prior to XOMA US’ acquisition of a Royalty
Interest, the economic value of the Royalty Interest is evaluated using a risk-adjusted discounted cash flow model (“DCF”). The DCF model separately identifies the value of the Development Milestone Receivables the Royalty Interest
is expected to generate and the value of the Sales-Based Receivables the Royalty Interest is expected to generate. When an acquisition includes a Royalty Interest in more than one Specified Product, all programs are included in the model to
determine a total value of the potential economics of the entire “basket” of assets.

 Once acquired, the purchase price of a
Royalty Interest is recorded on XOMA’s balance sheet as a “royalty and commercial payment receivable” in accordance with the requirements of US GAAP. For purposes of monitoring compliance with section 3(c)(5)(A), XOMA US
allocates a portion of the receivables balance attributable to the Royalty Interest to Development Milestone Receivables based on the pro-rata percentage of potential future economics the Royalty Interest is
expected to generate, as calculated in the DCF model prepared during the initial due diligence process. For example, if XOMA acquires a Royalty Interest for $10.0 million and the percentage of the DCF attributable to Development Milestone
Receivables is 10%, the Company will allocate $1.0 million as a Milestone Receivable and $9.0 million as a Sales-Based Receivable for purposes of monitoring its compliance with section 3(c)(5)(A). As payments pursuant to the Royalty
Interests are received, the Company applies the cash receipt against the Development Milestone Receivables first and then against the Sales-Based Receivables, consistent with the timeline of achievement under the applicable Royalty Interests. On a
quarterly basis, the Company calculates the total Sales-Based Receivables as a percentage of XOMA US’s total assets and confirms that the Sales-Based Receivables represent at least 55% of XOMA US’s total assets.

As of December 31, 2023, $60.0 million (or approximately 81%) of XOMA US’s total assets consisted of short-term and long-term
royalty and commercial receivables attributable to the Royalty Interests. Of this amount, $0.9 million has been attributed to Development Milestone Receivables and $59.1 million has been attributed Sales-Based Receivables. Consequently, as
of December 31, 2023, approximately 80% of XOMA US’s total assets represented the fair value of the Sales-Based Receivables attributable to XOMA US’s Royalty Interests. A spreadsheet providing a detailed breakdown of how these figures
have been calculated has been submitted to the Staff separately on a confidential basis.

 XOMA respectfully submits that the foregoing
model and accounting treatment are valid and appropriate support for XOMA’s claim that XOMA’s ownership interest in XOMA US may be treated as a “good asset” under the 40% test” established under section 3(a)(1)(C) of the
1940 Act. In particular, XOMA US is a “majority-owned subsidiary of XOMA (as such term is defined in section 3(a)(2) of the 1940 Act) because (i) XOMA US is a wholly-owned subsidiary of XOMA, and (ii) XOMA US is not an investment
company nor is it relying on the “private fund” exclusions set forth in sections 3(c)(1) or 3(c)(7) of the 1940 Act. Instead, XOMA US relies on the exclusion from the definition of an investment company set forth in section 3(c)(5)(A), as
interpreted by the Staff in the Royalty Pharma no-action letter (“Royalty Pharma”).1

1
 Royalty Pharma, SEC No-Action Letter, Ref. No. 20107221321
(Aug 13, 2010).

 3

 U.S. Securities and Exchange Commission

April 17, 2024

 In Royalty Pharma, the Staff provided no action assurance to Royalty Pharma (one of
XOMA’s primary competitors and most comparable reporting company) to the effect that Royalty Pharma could rely on the section 3(c)(5)(A) exclusion in connection with the purchase of pharmaceutical royalty entitlements. In so doing, the Staff
stated that the appropriate test under section 3(c)(5)(A) is “not whether the company is engaged in ‘sales financing,’ but whether there is a direct nexus between the obligation being purchased and the sale of specific merchandise or
services.” Applying this principle to Royalty Pharma’s business, the Staff stated that it would not recommend an enforcement action against Royalty Pharma for failing to register as an investment company under the 1940 Act in reliance on
the following representations from Royalty Pharma:

a)
 Royalty Pharma is primarily engaged in the business of purchasing royalty interests obligating others to pay
royalties to Royalty Pharma;

b)
 the royalty interests that Royalty Pharma owns entitle it to collect royalty receivables that are directly
based on the sales price of specific biopharmaceutical products that use intellectual property covered by specific license agreements; and

c)
 Royalty Pharma has not issued, and does not now issue or propose to issue, redeemable securities, face-amount
certificates of the installment type or periodic payment plan certificates.

 XOMA US fits squarely within the parameters
established under Royalty Pharma. As noted above, as of December 31, 2023, approximately 80% of XOMA US’s total assets consisted of Sales-Based Receivables, significantly above the 55% threshold applied in Royalty Pharma to
determine that Royalty Pharma was “primarily engaged” in the business of acquiring royalty interests. In addition, the Sales-Based Receivables are all directly based on the sales price of the Specified Products that utilize intellectual
property covered by XOMA US’s Royalty Interests. Finally, the only securities XOMA US has issued are the common equity ownership interests held by XOMA. XOMA US has not issued, nor does it propose to issue redeemable securities, face-amount
certificates of the installment type, or periodic payment plan certificates.

 For the reasons set forth above, XOMA respectfully submits
that (i) a direct nexus exists between the receivables that are carried on XOMA US’s balance that represent Sales-Based Receivables and the sale of the Specified Products, (ii) XOMA US may therefore rely on the exclusion from the
definition of an investment company provided under section 3(c)(5)(A) of the 1940 Act, as interpreted by the Staff in Royalty Pharma, and (iii) XOMA may therefore treat its ownership interest in XOMA US as a majority owned subsidiary (or
“good asset”) for purposes of complying with the “40% test” set forth in section 3(a)(1)(C) of the 1940 Act.

 4

 U.S. Securities and Exchange Commission

April 17, 2024

3.
 To the extent not addressed in your response to comment 2 above, please identify and discuss: (1) any
material differences between XOMA US’s royalty and commercial payment agreements and the analogous agreements involved in Royalty Pharma, SEC No- Action Letter (Aug. 13, 2010); and (2) any other
instances where XOMA US cannot make the representations contained in that letter.

 The Royalty Interests acquired by
XOMA US are not materially different from the analogous agreements described in Royalty Pharma. As noted above, at least some of the value of XOMA US’s Royalty Interests are attributable to Development Milestone Receivables. Such
receivables are not based on the sales price of the Specified Products. Nevertheless, as discussed above, XOMA US does not count the value of the Development Milestone Receivables, nor the revenue generated by them, towards its compliance with the
conditions of Royalty Pharma.

 We also note that, as discussed above, XOMA treats the value of the Sales-Based Threshold
Receivables it is entitled to receive under its Royalty Interests as Sales-Based Receivables. The Royalty Pharma no-action letter did not expressly address the treatment of any payments that Royalty
Pharma may receive based on the achievement of specified sales thresholds. Instead, Royalty Pharma focused on whether the royalty payments based on a percentage of the sales revenue generated by specific biopharmaceutical products satisfied
the “direct nexus” standard articulated by the Staff. Consistent with that standard, we believe that a direct nexus does exist between the Sales-Based Threshold Receivables and the sale of the Specified Products, insofar as the receipt of
payments under the Sales-Based Threshold Receivables provisions in the applicable Royalty Interests is contingent on and directly linked to sales of the Specified Products. Indeed, from an economic perspective, the Sales-Based Threshold Revenues are
no different from the Sales-Based Royalty Receivables insofar as they may be seen as merely entitling XOMA (US) to a “bonus” royalty payment (effectively increasing the percentage of sales revenues that XOMA (US) receives) if certain sales
thresholds are achieved.2

 *   *   *

2
 Even if the Staff were to disagree with this analysis, the elimination of the value of the Sales-Based
Threshold Receivables from the Sales-Based Receivables that XOMA uses to monitor compliance with Royalty Pharma would only lower the percentage of Sales-Based Receivables to total assets from approximately 80% to approximately 79%. Thus, the
categorization of the Sales-Based Threshold Receivables under the Royalty Pharma no-action letter does not have a material impact on the analysis presented above.

 5

 U.S. Securities and Exchange Commission

April 17, 2024

 Thank you for your consideration of this response. If you have any questions regarding the
response set forth above, please do not hesitate to call me at (415) 393-8373 or Branden C. Berns at (415) 393-4631.

Sincerely,

 /s/ Ryan A. Murr

Ryan A. Murr

cc:
 Brian Lane, Gibson, Dunn & Crutcher LLP

Branden C. Berns, Gibson, Dunn & Crutcher LLP

Owen Hughes, XOMA Corporation

Thomas Burns, XOMA Corporation

Christopher Baldwin, XOMA Corporation

 6

United States securities and exchange commission logo
April 3, 2024
Owen Hughes
Chief Executive Officer
XOMA Corporation
2200 Powell Street, Suite 310
Emeryville, CA 94608
Re:XOMA Corporation
Registration Statement on Form S-4
Response Dated March 22, 2024
File No. 333-277812
Dear Owen Hughes:
            We have reviewed your March 22, 2024 response to our comment letter and have the
following comments.
            Please respond to this letter by amending your registration statement and providing the
requested information. If you do not believe a comment applies to your facts and circumstances
or do not believe an amendment is appropriate, please tell us why in your response.
            After reviewing any amendment to your registration statement and the information you
provide in response to this letter, we may have additional comments. Unless we note otherwise,
any references to prior comments are to comments in our March 13, 2024 letter.
Response Dated March 22, 2024
General
1.Please supplement your response to prior comment 1 by (i) identifying the approximate
percentage of your total assets (exclusive of Government securities and cash items)
composed of your ownership interests in XOMA (US) LLC (“XOMA US”) and (ii)
identifying the types of assets categorized as cash and cash equivalents (e.g., demand
deposits or registered money market funds) currently held by you, together with their
approximate amounts.
2.Please supplement your response by providing your comprehensive, detailed legal
analysis supporting your contention that XOMA US is eligible for the 3(c)(5)(A)
exclusion in view of the fact that Section 3(c)(5)(A) is available only where an acquired
obligation represents part or all of the sales price of merchandise, insurance, and services.
In your response, please:

 FirstName LastNameOwen Hughes
 Comapany NameXOMA Corporation
 April 3, 2024 Page 2
 FirstName LastName
Owen Hughes
XOMA Corporation
April 3, 2024
Page 2
•Describe and discuss whether XOMA US’s royalty and commercial payment
purchase agreements entitle XOMA US to collect payments that are not directly
based on the sales price of specific biopharmaceutical products, including for
example in connection with (A) the meeting of certain regulatory, development, or
other milestones, or (B) biopharmaceutical products that either are not currently
identified or were not currently identified at the time of entry into the agreement; and
•Describe and discuss whether any of the recorded values of the XOMA US’s royalty
and commercial payment receivables (both short and long-term) are attributable to
such payment rights, and in what specific amounts.
3.To the extent not addressed in your response to comment 2 above, please identify and
discuss: (1) any material differences between XOMA US’s royalty and commercial
payment agreements and the analogous agreements involved in Royalty Pharma, SEC No-
Action Letter (Aug. 13, 2010); and (2) any other instances where XOMA US cannot make
the representations contained in that letter.
            Please contact Jason Drory at 202-551-8342 or Alan Campbell at 202-551-4224 with any
questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:       Branden C. Berns

CORRESP
1
filename1.htm

CORRESP

 Gibson, Dunn & Crutcher LLP

One Embarcadero Center, Suite 2600

 San Francisco, CA
94111-3715

 Tel 415.393.8200

 gibsondunn.com

 March 22, 2024

 EDGAR
CORRESPONDENCE

 U.S. Securities and Exchange Commission

Division of Corporation Finance

 Office of Life Sciences

100 F Street, N.E.

 Washington, D.C. 20549

Attn: Jason Drory and Alan Campbell

Re:
 XOMA Corporation

Registration Statement on Form S-3 filed on March 8, 2024 (File
No. 333-277794) and Registration Statement on Form S-4 filed on March 8, 2024 (File No. 333-277812)

Ladies and Gentlemen:

 On behalf of XOMA
Corporation (the “Company” or “XOMA”), this letter responds to the comment of the staff of the U.S. Securities and Exchange Commission – Division of Corporation Finance (the “Staff”) contained
in your letters, each dated March 13, 2024 (the “Comment Letters”), regarding the above-referenced Registration Statement on Form S-3 (File
No. 333-277794) and Registration Statement on Form S-4 (File No. 333-277812). The Staff’s comments, which are
identical in both Comment Letters, are set forth below, followed by the Company’s response. The Company’s responses are set forth in ordinary type below the Staff’s comments, which are set forth in bold type.

1.
 We note your disclosure in your annual report on Form 10-K for the
fiscal year ended December 31, 2023 that you do not intend to become regulated as an investment company under the Investment Company Act of 1940 and you do not believe you are an “investment company” under applicable SEC rules. Please
provide a detailed legal analysis as to why you should not be considered an “investment company” under the Investment Company Act of 1940.

The Company acknowledges the Staff’s comment and respectfully advises the Staff that XOMA is not an investment company, as such term is
defined under section 3(a)(1)(A) of the Investment Company Act of 1940, as amended (the “1940 Act”), because XOMA is primarily engaged in the business of being a biotech royalty aggregator and is not engaged in, nor holds itself out
as being engaged in, and does not propose to engage in, the business of investing, reinvesting or trading in securities.

 Abu Dhabi • Beijing
• Brussels • Century City • Dallas • Denver • Dubai • Frankfurt • Hong Kong • Houston • London • Los Angeles

Munich • New York • Orange County • Palo Alto • Paris • Riyadh • San Francisco • Singapore • Washington,
D.C.

 U.S. Securities and Exchange Commission

March 22, 2024

 Moreover, XOMA is not an investment company under the definition of an investment company
provided in section 3(a)(1)(C) of the 1940 Act, because, on an unconsolidated basis, less than 40% of XOMA’s assets consist of “investment securities,” as such term is defined in section 3(a)(1)(C)(2) of the 1940 Act. Key to this
analysis is the fact that the largest asset on XOMA’s unconsolidated balance sheet, by far, is its ownership interest in XOMA (US) LLC (“XOMA US”). XOMA has concluded that XOMA US is a majority-owned subsidiary of XOMA, as such
term is defined in section 3(a)(1)(C)(2) of the 1940 Act, for the following reasons:

•

 XOMA US is a 100% wholly owned subsidiary of XOMA; and

•

 XOMA US is not an investment company or relying on the exclusions from the definition of an investment company
provided in sections 3(c)(1) or 3(c)(7) of the 1940 Act in reliance on Section 3(c)(5)(A) of the 1940 Act, as interpreted by the Staff in Royalty Pharma, SEC No-Action Letter (Aug. 13, 2010) (the
“Royalty Pharma No-Action Letter”).

 In accordance with the
conditions set forth in the Royalty Pharma No-Action Letter: (i) XOMA US is primarily engaged in the business of purchasing royalty interests obligating others to XOMA US royalties on the sale of
pharmaceutical products, (ii) more than 55% of the value of XOMA US’s assets consists of royalty interests (as set forth in the Royalty Pharma No-Action Letter) that entitle XOMA US to collect
royalty receivables that are directly based on the sale price of specific biopharmaceutical products that use intellectual property covered by specific license agreements, and (iii) XOMA US has not issued, and does not now issue or propose to
issue, redeemable securities, face amount securities of the installment type or periodic payment plan certificates. Based on that analysis, XOMA has concluded that its ownership interest in XOMA US may be treated as an ownership interest in a
majority owned subsidiary (or a “good asset”) for purposes of applying the 40% test set forth in section 3(a)(1)(C) of the 1940 Act.

Accordingly, we believe that Xoma is not currently an “investment company” within the meaning of the 1940 Act. Further, XOMA
monitors its continuing compliance with definitional provisions of the 1940 Act on a quarterly basis and does not propose to engage in a business that would cause it to become an investment company under those provisions. 

***

 2

 U.S. Securities and Exchange Commission

March 22, 2024

 Thank you for your consideration of this response. If you have any questions regarding the
response set forth above, please do not hesitate to call me at (415) 393-8373 or Branden C. Berns at (415) 393-4631.

Sincerely,

 /s/ Ryan A. Murr

Ryan A. Murr

cc:
 Brian Lane, Gibson, Dunn & Crutcher LLP

Branden Berns, Gibson, Dunn & Crutcher LLP

Owen Hughes, XOMA Corporation

Thomas Burns, XOMA Corporation

Christopher Baldwin, XOMA Corporation

 3

United States securities and exchange commission logo
March 13, 2024
Owen Hughes
Chief Executive Officer
XOMA Corporation
2200 Powell Street, Suite 310
Emeryville, CA 94608
Re:XOMA Corporation
Registration Statement on Form S-3
Filed March 8, 2024
File No. 333-277794
Dear Owen Hughes:
            We have conducted a limited review of your registration statement and have the
following comment.
            Please respond to this letter by amending your registration statement and providing the
requested information. If you do not believe our comment applies to your facts and
circumstances or do not believe an amendment is appropriate, please tell us why in your
response.
            After reviewing any amendment to your registration statement and the information you
provide in response to this letter, we may have additional comments.
Registration Statement on Form S-3 filed March 8, 2024
General
1.We note your disclosure in your annual report on Form 10-K for the fiscal year ended
December 31, 2023 that you do not intend to become regulated as an investment company
under the Investment Company Act of 1940 and you do not believe you are an
“investment company” under applicable SEC rules. Please provide a detailed legal
analysis as to why you should not be considered an “investment company” under the
Investment Company Act of 1940.
            We remind you that the company and its management are responsible for the accuracy
and adequacy of their disclosures, notwithstanding any review, comments, action or absence of
action by the staff.

 FirstName LastNameOwen Hughes
 Comapany NameXOMA Corporation
 March 13, 2024 Page 2
 FirstName LastName
Owen Hughes
XOMA Corporation
March 13, 2024
Page 2
            Refer to Rules 460 and 461 regarding requests for acceleration. Please allow adequate
time for us to review any amendment prior to the requested effective date of the registration
statement.
            Please contact Jason Drory at 202-551-8342 or Alan Campbell at 202-551-4224 with any
other questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:       Branden C. Berns

United States securities and exchange commission logo
March 17, 2021
James R. Neal
Chief Executive Officer
XOMA Corporation
2200 Powell Street, Suite 310
Emeryville, CA 94608
Re:XOMA Corporation
Registration Statement on Form S-3
Filed March 10, 2021
File No. 333-254073
Dear Mr. Neal:
            This is to advise you that we have not reviewed and will not review your registration
statement.
            Please refer to Rules 460 and 461 regarding requests for acceleration.  We remind you
that the company and its management are responsible for the accuracy and adequacy of their
disclosures, notwithstanding any review, comments, action or absence of action by the staff.
            Please contact Deanna Virginio at 202-551-4530 with any questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:       Michael Tenta, Esq.

CORRESP
1
filename1.htm

CORRESP

 XOMA CORPORATION

2200 Powell Street, Suite 310

Emeryville, California 94608

 (510)
204-7200

 March 17, 2021

VIA EDGAR

 United States
Securities and Exchange Commission

 Division of Corporation Finance

100 F Street, N.E.

 Washington, D.C. 20549

Attn: Deanna Virginio

RE:
 XOMA Corporation

Registration Statement on Form S-3

File No. 333-254073

Ladies and Gentlemen:

 XOMA Corporation hereby requests that
the Securities and Exchange Commission take appropriate action to cause the above-referenced Registration Statement on Form S-3 to become effective on March 19, 2021, at 4:00 p.m., Eastern Time, or as
soon thereafter as is practicable.

Very truly yours,

XOMA Corporation

By:

 /s/ Thomas Burns

Thomas Burns

Senior Vice President, Finance and Chief
Financial Officer

CORRESP
1
filename1.htm

CORRESP

 April 3, 2018

VIA EDGAR

 Division of Corporate Finance

U.S. Securities and Exchange Commission

 100 F Street, N.E.

Washington, D.C. 20549

 Attn: Jeff Gabor

RE:
XOMA Corporation

Registration Statement on Form S-3

File No. 333-223493

 Ladies and Gentlemen:

Pursuant to Rule 461 under the Securities Act of 1933, as amended, the undersigned registrant hereby requests that the Securities and Exchange
Commission (the “Commission”) take appropriate action to cause the above-referenced Registration Statement on Form S-3 to become effective at 4:00 p.m. Eastern Time on April 5, 2018, or as soon thereafter as is
practicable.

Sincerely,

XOMA Corporation

By:

 /s/ Thomas Burns

Thomas Burns

Senior Vice President, Finance and
Chief Financial Officer

cc:
Michael E. Tenta

Cooley LLP

Mail Stop 4 546
September 7, 2016

John Varian
Chief Executive Officer
XOMA Corporation
2910 Seventh Street
Berkeley,  California 94710

Re: XOMA Corporation
 Preliminary Proxy Statement on Schedule 14A
Filed September 2, 2016
File No. 000 -14710

Dear Mr. Varian :

We have completed our review of your filing .  We remind you that our comments or
changes to disclosure in response to our comments do not foreclose the Commission from taking
any action with respect to the company or the filing and the company may not assert staff
comments as a defense in any proceeding initiated by the Commission or any person under the
federal securities laws of the United States.  We urge all persons who are responsible for the
accuracy and adequacy of the disclosure in the filing to be certain that the filing includes the
information the Securities Exchange Act of 1934 and all applicable rules require.

Sincerely,

 /s/ Erin K. Jaskot, for

Suzanne Hayes
Assistant Director
Office of Healthcare and Insurance

CORRESP
1
filename1.htm

CORRESP

 Jim Fulton

 T: +1 212 479 6103

fultonjf@cooley.com

VIA EDGAR AND EMAIL

 September 6, 2016

 United
States Securities and Exchange Commission

 Division of Corporation Finance

100 F Street, N.E.

 Washington, D.C. 20549

Attn:
Dorrie Yale

 Erin Jaskot

Suzanne Hayes

Re:
XOMA Corporation

 Preliminary Proxy Statement on Schedule 14A

Filed September 2, 2016

File No. 000-14710

 Dear Ms. Yale:

 On behalf of our client, XOMA Corporation (the “Company”), this letter is being transmitted in response to a comment received
from the staff (the “Staff”) of the Securities and Exchange Commission, by letter dated September 6, 2016 (the “Comment Letter”), regarding the Company’s Preliminary Proxy Statement on
Schedule 14A, filed on September 2, 2016 (the “Proxy Statement”). The Company is concurrently submitting a revised version of the Proxy Statement (the “Revised Proxy Statement”), including changes
in response to the Staff’s comment.

 The text of the Staff’s comment has been included in this letter in italics for your convenience, and we
have numbered the paragraph below to correspond to the numbering of the Comment Letter.

 Staff Comments and Company Responses

Proposal No. 1, page 6

1.
We note your disclosure that the reverse stock split would not change the number of authorized shares of common stock and that these additional shares may be used for various purposes. Please revise your
filing to disclose whether or not you have any plans, arrangements, understandings, or commitments to issue any of the shares that would be newly available for issuance as a result of the reverse split. If you have any such plans, etc., please
describe them in this proposal. Please also amend your disclosure to discuss the anti-takeover effects of the increase in newly-authorized but unissued shares of common stock that will result from the reverse stock split.

 1114 AVENUE OF THE
AMERICAS, NEW YORK, NY 10036-7798 T: (212) 479-6103 F: (212) 479-6275 WWW.COOLEY.COM

 United States Securities and Exchange Commission

September 6, 2016

 Page 2 of 2

 Response: The Company acknowledges the Staff’s comment and has provided additional disclosure on
page 7 of the Revised Proxy Statement in response to the Staff’s comment.

 Per your request, attached as Exhibit A hereto is a written
statement from the Company acknowledging that:

•

the company is responsible for the adequacy and accuracy of the disclosure in the filing;

•

staff comments or changes to disclosure in response to staff comments do not foreclose the Commission from taking any action with respect to the filing; and

•

the company may not assert staff comments as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

Please contact me at (212) 479-6103 with any questions or further comments regarding the Company’s response to the Comment Letter.

Sincerely,

 Cooley LLP

 /s/ Jim Fulton, Esq.

Jim Fulton, Esq.

cc:
Denis Quinlan, XOMA Corporation

 Thomas Burns, XOMA Corporation

Michael Tenta, Cooley LLP

 Marina
Remennik, Cooley LLP

 1114 AVENUE OF THE
AMERICAS, NEW YORK, NY 10036-7798 T: (212) 479-6103 F: (212) 479-6275 WWW.COOLEY.COM

 EXHIBIT A

 September 6, 2016

 Via
EDGAR and Email

 United States Securities and Exchange Commission

Division of Corporation Finance

 100 F Street, N.E.

Washington, D.C. 20549

Attn.:
Dorrie Yale

 Erin Jaskot

Suzanne Hayes

Re:
XOMA Corporation

 Preliminary Proxy Statement on Schedule 14A

Filed September 2, 2016

File No. 000-14710

 Dear Ms. Yale:

 Regarding the Company’s Preliminary Proxy Statement on Schedule 14A, filed on September 2, 2016, the Company hereby acknowledges that:

•

the company is responsible for the adequacy and accuracy of the disclosure in the filing;

•

staff comments or changes to disclosure in response to staff comments do not foreclose the Commission from taking any action with respect to the filing; and

•

the company may not assert staff comments as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

Sincerely,

XOMA CORPORATION

By:

 /s/ Denis Quinlan

    Denis Quinlan

    Senior Corporate Counsel and Secretary

 cc:

    Thomas Burns, XOMA Corporation

    Jim Fulton, Cooley LLP

    Michael Tenta, Cooley LLP

    Marina Remennik, Cooley LLP

Mail Stop 4 546
September 6, 2016

John Varian
Chief Executive Officer
XOMA Corporation
2910 Seventh Street, Berkeley,
California 94710

Re: XOMA Corporation
 Preliminary Proxy Statement on Schedule 14A
Filed September 2, 2016
File No. 000-14710

Dear Mr. Varian :

We have reviewed your filing an d have the following comment.  In some of our
comments, we may ask you to provide us with information so we may better understand your
disclosure.

Please respond to this comment  within ten busine ss days by providing the requested
information or advis e us as soon as possible when you will respond.  If you  do not believe our
comment  applies to your facts and circ umstances , please tell us why in your response.

After reviewing your response to this comment, we may have  additional comments.

Proposal No. 1, page 6

1. We note your disclosure that the reverse stock split would not change the number of
authorized shares of common stock and that these additional shares may be used for
various purposes .  Please revise your filing  to disclose whether or not you have any plans,
arrangements, understandings, or commitments to issue any of the shares that would be
newly available for issuance as a result of the reverse split.  If you have any such plans,
etc., please describe them in this proposal.   Please also amend your disclosure to discuss
the anti -takeo ver effects of the increase in newly -authorized but unissued shares of
common stock that will result from the  reverse stock split .

We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the filing to be certain that the filing includes the informatio n the Securities Exchange Act of
1934 and all applicable Exchange Act rules require.   Since the company and its management are
in possession of all facts relating to a company’s disclosure, they are responsible for the accuracy
and adequacy of the disclosu res they have made.

John Varian
XOMA Corporation
September 6, 2016
Page 2

  In responding to our comments, please provide  a written statement from the company
acknowledging that:

 the company is responsible for the adequacy and accuracy of the disclosure in the filing;

 staff comments or changes to disclosur e in response to staff comments do not foreclose
the Commission from taking any action with respect to the filing; and

 the company may not assert staff comments as a defense in any proceeding initiated by
the Commission or any person under the federal securities laws of the United States.

Please contact Dorrie Yale at 202-551-8776  or Erin Jaskot, Special Counsel, at 202 -551-
3442  with any questions.

Sincerely,

 /s/ Erin K. Jaskot, for

Suzanne Hayes
Assistant Director
Office of Healthcare and Insurance

cc:  Marina Remennik  — Cooley LLP

July 16 , 2013

Via E -mail
Fred Kurland
Chief Financial Officer
XOMA Corporation
2910 Seventh Street
Berkeley, CA 94710

Re: XOMA Corporation
Form 10 -K for the Fiscal year Ended December 31, 2012
Filed March 12 , 2013
File No. 000 -14710

Dear Mr. Kurland :

We have completed our review of your filing .  We remind you that our comments or
changes to disclosure in response to our comments do not foreclose the Commission from taking
any action with respect to the company or the filing and the company may not assert staff
comments as a defense in any proceeding initiated by the Commission or any person under the
federal securities laws of the United States.  We urge all persons who are re sponsible for the
accuracy and adequacy of the disclosure in the filing to be certain that the filing include the
information the Securities Exchange Act of 1934 and all applicable rules require.

Sincerely,

        /s/ Jeffrey P. Riedler

 Jeffrey P. Riedler
Assistant Director

CORRESP
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    corresp_071013.htm

July 10, 2013

Via EDGAR and Overnight Delivery

United States Securities and Exchange Commission

Division of Corporation Finance

100 F Street, N.E.

Washington, D.C. 20549

Attention:

Jeffrey P. Riedler

Austin Stephenson

Re:

XOMA Corporation

Form 10-K for the fiscal year ended December 30, 2012

Filed on March 12, 2013

File No. 000-14710

Ladies and Gentlemen:

XOMA Corporation, a corporation organized under the laws of the State of Delaware (“XOMA”) submits this letter in response to comments from the staff (the “Staff”) of the Securities and Exchange Commission (the “Commission”) sent via e-mail July 1, 2013, to Mr. Fred Kurland, Chief Financial Officer of XOMA, relating to the above-referenced filing.

This letter includes, in italicized and bold typeface, the Staff’s comments 1 and 2 contained in its July 1, 2013 letter, and we follow each of those comments with XOMA’s response in Roman typeface.

Form 10-K for the fiscal year ended December 31, 2012

Filed on March 12, 2013

Technologies and Technology Licenses.

1.

In this section you identify three trademarked core technologies, ADAPT, ModulX, and OptimX, which are owned by you and available for licensing to other companies. We also note the disclosure on page 28 which indicates that you have licensed some of your technology from other parties. If these technologies have been key to the development of your product pipeline and you have licensed any of these core technologies from third parties, please identify the third parties, file all material licensing agreements, and describe the material terms of these agreements. Alternatively, if you believe that the development of your product pipeline is not substantially dependent upon maintaining any or all of these agreements, please provide us a substantive analysis supporting your conclusions.

United States Securities and Exchange Commission

July 10, 2013

Page 2

In response to the Staff’s comment 1, we respectfully advise the Staff that the development of XOMA’s product pipeline, at present, is not substantially dependent upon maintaining material licensing agreements.

In the past, XOMA’s core technologies were substantially supported by licensing arrangements with other bio-technology companies.  The material terms of those in-licensing arrangements were disclosed by XOMA, and the agreements were filed as exhibits to XOMA’s filings with the Commission.  For example, on page 7 of Form 10-K for the fiscal year ended December 31, 2002, XOMA (then known as XOMA Ltd.) disclosed the material terms of cross-licensing arrangements with MorphoSys AG, Biosite Incorporated, Dyax Corp. and Cambridge Antibody Technology Limited and filed those agreements as exhibits.

However, XOMA’s core technologies as they are currently employed no longer substantially depend upon in-licensed technology.  Most of our in-licensed technologies have been superseded by proprietary technologies developed internally or have reached patent expiration or become obsolete for purposes of our current product pipeline.

In our future Annual Report on Form 10-K and Quarterly Report on Form 10-Q filings, we will revise the risk factor as follows (updated as appropriate from period to period):

“Certain of our technologies are in-licensed from third parties, so our capabilities using them are restricted and subject to additional risks.

“We license technologies from third parties.  These technologies include but are not limited to phage display technologies licensed to us in connection with our bacterial cell expression technology licensing program.  However, our use of these technologies is limited by certain contractual provisions in the licenses relating to them, and although we have obtained numerous licenses, intellectual property rights in the area of phage display are particularly complex.  Our licensors may not be successful in prosecuting the patent applications to which we have licenses, or our licensors may fail to maintain existing patents.  They may determine not to pursue litigation against other companies that are infringing these patents, or they may pursue such litigation less aggressively than we would.  Our licensors also may seek to terminate our license, which could cause us to lose the right to use the licensed intellectual property.”

United States Securities and Exchange Commission

July 10, 2013

Page 3

Patents and Trade Secrets, pages 18-19

2.

In the second paragraph you identify ten different patents that relate to your gevokizumab product. We note that two of these patents relate to the Type 2 diabetes program, one relates to the osteoarthritis program, one relates to the cancer program, and another relates to the coronary program. You do not specify to which gevokizumab programs the five other patents apply. You should disclose to which programs these five other patents apply. If these apply to the use of gevokizumab generally you should clarify. In any case, you should identify the patents that apply to the treatment of NIU and Behcet’s uveitis, as these indications are the most advanced. Please also separately disclose the year of expiration of each of the ten patents you identify as being related to gevokizumab and the nature of the patent or type of patent protection applying to each. Additionally, please clarify as to each of the patents related to gevokizumab whether they were in-licensed from Les Laboratoires Servier or some other third party, or developed in-house and filed with the Patent and Trademark Office by the registrant.

In response to the Staff’s comment 2, in our future Annual Report on Form 10-K, we will disclose the following (updated as appropriate from period to period):

“Patents and Trade Secrets

“. . .

“We have established a portfolio of patents in the U.S., Europe and certain other countries for our gevokizumab program, the longest of which expires in 2027.  U.S. Patent Nos. 7,531,166 and 7,582,742 cover gevokizumab as well as related antibodies and nucleic acids, expression vectors and production cell lines for the manufacture of such antibodies.  U.S. Patent Nos. 7,744,865, 7,744,866 and 7,943,121 relate to additional IL-1 beta binding antibodies.  These five patents cover gevokizumab as well as related antibodies.  Also, these five patents, in addition to recently issued U.S. Patent No. 8,377,442, cover gevokizumab as a method for the treatment of uveitis (e.g., NIU and Behçet’s uveitis). U.S. Patent No. 7,695,717 relates to methods of treating certain IL-1 related inflammatory diseases, including rheumatoid arthritis and osteoarthritis, with gevokizumab as well as related antibodies. U.S. Patent Nos. 7,695,718 and 8,101,166 relate to methods of treating Type 2 diabetes with certain antibodies that bind to IL-1 beta, including gevokizumab as well as related antibodies. U.S. Patent No. 7,829,093 relates to methods of treating diabetes mellitus (“Type 1”) with gevokizumab as well as related antibodies.  U.S. Patent No. 7,829,094 relates to methods of treating certain cancers with gevokizumab as well as related antibodies, with the cancer being selected from multiple myeloma, acute myelogenous leukemia and chronic myelogenous leukemia.  U.S. Patent No. 7,988,968 relates to methods of treating certain IL-1 beta related coronary conditions, including myocardial infarction, with gevokizumab as well as related antibodies.  The following table lists each patent, its expiration date along with a description of the nature or type of patent protection provided.

United States Securities and Exchange Commission

July 10, 2013

Page 4

Patent No.

Issue Date

Current Expiration Date (including PTA)*

Type of Patent Protection

7,531,166

05-12-2009

03-01-2027

Composition

7,582,742

09-01-2009

06-21-2026

Composition

7,695,717

04-13-2010

06-21-2026

Method

7,695,718

04-13-2010

12-20-2027

Method

7,744,865

06-29-2010

06-21-2026

Composition

7,744,866

06-29-2010

06-21-2026

Composition

7,829,093

11-09-2010

06-21-2026

Method

7,829,094

11-09-2010

06-21-2026

Method

7,988,968

08-02-2011

06-21-2026

 Method

7,943,121

05-17-2011

06-21-2026

Composition

8,101,166

01-24-2012

12-20-2027

Method

8,377,442

02-19-2013

06-21-2027

Method

*PTA= Patent Term Adjustment

“All of the claims of these patents cover gevokizumab, related antibodies and their uses and are owned by XOMA.  None of these patents were in-licensed from our partner Servier.  Also, patents have been granted by the European Patent Office and certain other countries for gevokizumab, as well as nucleic acids, expression vectors and production cell lines for the manufacture of gevokizumab.”

In responding to your comments, XOMA acknowledges that:

1.

XOMA is responsible for the adequacy and accuracy of the disclosures in its filings;

2.

Staff comments or changes to disclosures in response to the Staff’s comments do not foreclose the Commission from taking any action with respect to XOMA’s filings; and

3.

XOMA may not assert the Staff’s comments as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

United States Securities and Exchange Commission

July 10, 2013

Page 5

Please direct your questions or comments to me by telephone at (510) 204-7234.  In addition, we respectfully request that you provide any additional comments you may have to my attention by email to Kurland@XOMA.com or by mail to XOMA’s offices at 2910 Seventh Street, Berkeley, California 94710.

Thank you for your assistance.

Very truly yours,

XOMA Corporation

/s/ FRED KURLAND

Fred Kurland

Vice President, Finance, Chief Financial Officer and Secretary

cc:       Russell J. Wood, Esq.

July 1 , 2013

Via E -mail
Fred Kurland
Chief Financial Officer
XOMA Corporation
2910 Seventh Street
Berkeley, CA 94710

Re: XOMA Corporation
Form 10 -K for the Fiscal year Ended December  31, 2012
Filed March 12 , 2013
File No. 000 -14710

Dear Mr. Kurland :

We have reviewed your filing and have the following comment s. In our comment s, we
may ask you to provide us with infor mation so we may better understand your disclosure.

Please respond to this letter within 10 business days by providing the requested
infor mation or by advising us when you will provide the requested response .  If you do  not
believe our comment s apply  to your facts and circu mstances , please tell us why in your
response.

After revie wing the infor mation you provide  in response to these  comments, we may
have additio nal co mments.

Technologies and Technology Licenses, page 6

1. In this section you identify three trademarked core technologies, ADAPT, ModulX , and
OptimX, which are owned by you and available for licensing to other companies.   We
also note the disclosure on page 28 which indicates that you have licensed some of your
technology from other parties.   If these technologies have been key to the developme nt of
your product pipeline and you have licensed any of these core technologies from third
parties , please identify the third parties, file all material licensing agreements , and
describe the material terms of these agreements.   Alternatively, if you beli eve that the
development of your product pipeline is not substantially dependent upon maintaining
any or all of these agreements , please provide us a substantive analysis supporting your
conclusions.

Fred Kurland
XOMA Corporation
July 1 , 2013
Page 2

 Patents and Trade Secrets, pages 18 -19

2. In the secon d paragraph you identify ten different patents that relate to your gevokizumab
product.  We note that two of these patents relate to the Type 2 diabetes program, one
relates to the osteoarthritis program, one relates to the cancer program , and another
relates to the coronary program.   You do not specify to which gevokizumab programs the
five other patents apply. You should disclose to which programs these five other patents
apply.  If these apply to the use of gevokizumab generally you should clarify.  In any
case, you should identify the patents that  apply to the treatment of NIU and Behcet’s
uveitis , as these indications are the most advanced.  Please also separately disclose the
year of expiration of  each of the ten patents you identify as being related to gevokizumab
and the nature of the patent or type of patent protection applying to each . Additionally ,
please clarify as to each of the patents related to gevokizumab whether they were in -
licensed from Les Laboratoires Servier or some other third party , or developed in -house
and filed with the P atent and Trademark Office by the registrant.

We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the filing to be certain that the filing includes all information the Securities Exchange Act of
1934 and all applicable Exchange Act rules require .  Since the company and its management are
in possession of all facts relating to a company’s disclosure, they are responsible for the accuracy
and adequacy of the disclosures they have made.

In responding to our comments, please provide a written statement from the company
acknowledging that :

 the company is responsible for the adequacy and accuracy of the disclosure in the filing ;

 staff comments or changes to disclosure in response to staff comments do not fore close
the Commission from taking any action with respect to the filing ; and

 the company may not assert staff comment s as a defense in any proceeding initiated by
the Commission or any person under the federal securities laws of the United States .

Please  contact Austin Stephenson at (202) 551 -3192 or me at (202) 551 -3715 with any
questions.

Sincerely,

 /s/ Jeffrey P. Riedler

 Jeffrey P. Riedler
Assistant Director

CORRESP
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    corresp.htm

June 3, 2011

Securities and Exchange Commission

100 F Street, N.E.

Washington, D.C. 20549

Attention:

Johnny Gharib

Division of Corporation Finance

Re:

XOMA Ltd.

Registration Statement on Form S-3

File No. 333-172197

Filed February 11, 2011

Ladies and Gentlemen:

Pursuant to Rule 461 under the Securities Act of 1933, the undersigned, being the issuer of securities to which the referenced Registration Statement relates, respectfully requests that the effectiveness of the Registration Statement be accelerated so that it will become effective at 12:00 P.M. on June 6, 2011 or as soon thereafter as practicable.

The disclosure in the filing is the responsibility of XOMA Ltd. (the “Company”).  The Company acknowledges that:

·

should the Commission or the staff, acting pursuant to delegated authority, declare the filing effective, it does not foreclose the Commission from taking any action with respect to the filing;

·

the action of the Commission or the staff, acting pursuant to delegated authority, in declaring the filing effective, does not relieve the Company from its full responsibility for the adequacy and accuracy of the disclosure in the filing; and

·

the Company may not assert staff comments and the declaration of effectiveness as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

Very truly yours,

XOMA Ltd.

By:  /s/ Christopher J. Margolin

       Christopher J. Margolin

       Vice President, General

        Counsel and Secretary

CORRESP
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    corresp.htm

May 27, 2011

Securities and Exchange Commission

100 F Street, N.E.

Washington, D.C. 20549

Attention:

Johnny Gharib

Division of Corporation Finance

Re:

XOMA Ltd.

Registration Statement on Form S-3

File No. 333-172197

Filed February 11, 2011

Ladies and Gentlemen:

Pursuant to Rule 461 under the Securities Act of 1933, the undersigned, being the issuer of securities to which the referenced Registration Statement relates, respectfully requests that the effectiveness of the Registration Statement be accelerated so that it will become effective at 4:00 P.M. on May 31, 2011 or as soon thereafter as practicable.

The disclosure in the filing is the responsibility of XOMA Ltd. (the “Company”).  The Company acknowledges that:

·

should the Commission or the staff, acting pursuant to delegated authority, declare the filing effective, it does not foreclose the Commission from taking any action with respect to the filing;

·

the action of the Commission or the staff, acting pursuant to delegated authority, in declaring the filing effective, does not relieve the Company from its full responsibility for the adequacy and accuracy of the disclosure in the filing; and

·

the Company may not assert staff comments and the declaration of effectiveness as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

Very truly yours,

XOMA Ltd.

By:  /s/ Christopher J. Margolin

        Christopher J. Margolin

        Vice President, General

        Counsel and Secretary

CORRESP
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[Letterhead of Cahill Gordon & Reindel llp]

(212) 701-3313

March 18, 2011

Re:

XOMA Ltd.

Registration Statement on Form S-3

Filed February 11, 2011

File No. 333-172197

Dear Mr. Riedler:

This letter is submitted on behalf of XOMA Ltd. (the “Company”) in response to your comment letter dated February 16, 2011 relating to the Company’s Registration Statement on Form S-3 (File No. 333-172197), filed on February 11, 2011 (the “Registration Statement”), and in conjunction with the filing of Amendment No. 1 to the Registration Statement, filed on March 10, 2011 (the “Amendment”).

In response to your comment, as requested, the Company has revised the disclosure to specifically state that McNicoll, Lewis & Vlak LLC is an underwriter, which revisions are reflected on the cover page and in the “Plan of Distribution” section of the MLV sales agreement prospectus in the Amendment.

-2-

Your attention to this filing and this response is greatly appreciated.  Any questions or further comments regarding this filing should be directed to the undersigned at the number indicated above.

Sincerely,

Geoffrey E. Liebmann

Mr. Jeffrey Riedler

Assistant Director

Division of Corporation Finance

US Securities and Exchange Commission

100 F Street, N.E.

Washington, DC 20549

VIA ELECTRONIC SUBMISSION AND FACSIMILE

cc:

Johnny Gharib, Division of Corporation Finance

Christopher J. Margolin, XOMA Ltd.

February 16, 2011

Christopher J. Margolin, Esq. XOMA Ltd. 2910 Seventh Street Berkeley, California 94710

Re: XOMA Ltd.
  Registration Statement on Form S-3
Filed February 11, 2011
  File No. 333-172197

Dear Mr. Margolin:
 We have limited our review of your regist ration statement to the resolution of your
pending confidential treatment request filed on November 12, 2010 and the issue we have addressed in our comment.
 Please respond to this letter by amending your registration statement and providing the
requested information.  Where you do not believe our comment applies to your facts and circumstances or do not believe an amendment is appropriate, please tell us why in your
response.
 After reviewing any amendment to your regi stration statement, we may have additional
comments.
 1. Please revise the cover page and “Plan of  Distribution” section of the MLV sales
agreement prospectus to specifically na me McNicoll, Lewis & Vlak LLC as an
underwriter.

We urge all persons who are responsible for th e accuracy and adequacy of the disclosure
in the filing to be certain that the filing incl udes the information the Securities Act of 1933 and
all applicable Securities Act rules require.  Since the company and its management are in
possession of all facts relating to a company’s disclosure, they are responsible for the accuracy and adequacy of the disclosures they have made.
Notwithstanding our comments, in the event you request acceleration of  the effective date
of the pending registration statement please pr ovide a written statement from the company
acknowledging that:

• should the Commission or the staff, acting purs uant to delegated authority, declare the
filing effective, it does not foreclose the Co mmission from taking any action with respect
to the filing;

Christopher J. Margolin XOMA Ltd. February 16, 2011 Page 2

• the action of the Commission or the staff, acting pursuant to delegated authority, in
declaring the filing effective, does not relieve the company from its full responsibility for
the adequacy and accuracy of the disclosure in the filing; and

• the company may not assert staff comments a nd the declaration of effectiveness as a
defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.  Please refer to Rules 460 and 461 regarding re quests for acceleration.  We will consider a
written request for acceleration of  the effective date of the regi stration statement as confirmation
of the fact that those reques ting acceleration are aware of thei r respective responsibilities under
the Securities Act of 1933 and the Securities Excha nge Act of 1934 as they relate to the proposed
public offering of the securities specified in the above registration stat ement.  Please allow
adequate time for us to review any amendment prior to the requested effective date of the registration statement.
 Please contact Johnny Gharib at (202) 551- 3170 or me at (202) 551-3715 with any
questions.
Sincerely,
       Jeffrey Riedler
Assistant Director

January 19, 2011
 Steven B. Engle Chairman, Chief Executive Officer and President XOMA Ltd. 2910 Seventh Street Berkeley, California 94710
 Re: XOMA Ltd.
 Form 10-K for the Fiscal Year Ended December 31, 2009
  Filed March 11, 2010
  Form 10-K/A filed April 30, 2010   Form 10-K/A filed December 27, 2010   File No. 000-14710

 Dear Mr. Engle:
  We have completed our review of your fili ngs and do not have any further comments at
this time.
Sincerely,

Jeffrey P. Riedler Assistant Director

cc: Kimberly C. Petillo (Cahill Gordon & Reindel LLP)

CORRESP
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    xoma10k_112410.htm

[On Cahill Gordon & Reindel LLP Letterhead]

(212) 701-3265

November 24, 2010

       Re:  XOMA Ltd.

                                        Form 10-K for the Fiscal Year Ended December 31, 2009

                                Filed March 11, 2010

              Form 10-K/A filed April 30, 2010

              File No. 000-14710

Dear Mr. Riedler:

On behalf of and as counsel to XOMA Ltd. (the “Company”), we are responding to your letter dated October 20, 2010 (the “Comment Letter”) relating to the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2009 (the “Form 10-K”), filed with the Securities and Exchange Commission (the “SEC”) on March 11, 2010, and Amendment No. 1 on Form 10-K/A filed with the SEC on April 30, 2010 (the “Form 10-K/A”) (File No. 000-14710).

For your convenience, the Company’s responses below are numbered to correspond to the comments in the Comment Letter (the “Comments”).

Compensation Components

1.

We note your response to our prior comment 3 and we reissue the comment.  Please further revise the provided draft disclosure to discuss the actual long-term incentive award made to each named executive officer for the 2009 fiscal year and the conclusions reached by the compensation committee in determining each award.  Your disclosure should discuss how each factor considered by the committee was evaluated or measured and how the totality of the factors resulted in the long-term incentive award made to each named executive officer.

Response:  Attached to this letter as Annex 1 is revised disclosure, marked to show changes from the draft disclosure previously provided, which we believe addresses the staff’s concerns as expressed in this Comment.

Cash Bonus Plans

2.

We note your response to our prior comment 4.  Please further revise the provided draft disclosure to discuss the “individual and performance objectives” referenced throughout your discussion of the Management Incentive Compensation Plan.  Your discussion should include not only the objectives themselves but also the extent to which each objective was achieved and how such level of achievement affected the actual bonus awarded to each named executive officer.

Response:  Attached to this letter as Annex 2 is revised disclosure, marked to show changes from the draft disclosure previously provided, which we believe addresses the staff’s concerns as expressed in this Comment.

In addition, the Company acknowledges that:

·

the Company is responsible for the adequacy and accuracy of the disclosure in the filing;

·

staff comments or changes to disclosure in response to staff comments do not foreclose the Commission from taking any action with respect to the filing; and

·

the Company may not assert staff comments as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

The Company believes that the response set forth above is responsive to the Comment.  Please direct any questions or further comments regarding this filing to the undersigned at the number indicated above.

Sincerely,

/s/ Kimberly C. Petillo

Kimberly C. Petillo

Jeffrey Riedler

Assistant Director

Division of Corporation Finance

Securities and Exchange Commission

100 F Street, N.E.

Washington, D.C.  20549

VIA ELECTRONIC TRANSMISSION/BY HAND

cc:

Laura Crotty

Christopher J. Margolin

Geoffrey E. Liebmann

Annex 1

       Long-Term Incentive Program .    Long-term incentive compensation principally takes the form of incentive and non-qualified option grants pursuant to shareholder-approved equity-based compensation plans. These grants are designed to promote the convergence of long-term interests between the Company’s key employees and its shareholders; specifically, the value of options granted will increase or decrease with the value of the Company’s Common Shares. In this manner, key individuals are rewarded commensurately with increases in shareholder value. These grants also typically include a 4-year vesting period to encourage continued employment. The size of a particular option grant is determined based on the individual’s position and contribution to the Company.

For grants during 2009, the number of options granted were determined based on employee performance and perceived potential, the numbers of options granted to such individuals in the previous fiscal year, the aggregate number of options held by each such individual, the number of options granted to similarly situated individuals in the pharmaceutical and biotechnology industries, the price of the Company’s Common Shares relative to other companies in such industries and the resulting relative value of such options; although.  Although no specific measures of corporate performance were considered, the fact that no incentive compensation was awarded under the Company’s incentive compensation plans for 2008, notwithstanding that management had successfully achieved a percentage of the 2008 objectives under such plans in excess of the minimum required to make awards, was considered.

In February of 2009, Mr. Engle was granted options to purchase 600,000 common shares and Dr. Scannon and Messrs. Kurland, Margolin and Wells were each granted options to purchase 200,000 common shares.  These numbers were arrived at after consideration of the factors described in the foregoing paragraph, without any of such factors being assigned a specific weighting or measured against quantified criteria, except when considering the number of options granted to similarly situated individuals in the pharmaceutical and biotechnology industries.  In considering that factor, the number of options granted was benchmarked against the 25th percentile of the peer group companies.  This percentile was selected over the initially recommended 50th percentile in light of the limited number of shares then available for grant under the Company’s long-term incentive plans.

Historically, theseoption grants intended as long-term incentive compensation have been made pursuant to the Company’s 1981 Share Option Plan (the “Option Plan”) and Restricted Share Plan (the “Restricted Plan”). In May of 2010, the Compensation Committee and the full Board adopted, subject to shareholder approval, a new equity-based compensation plan, the 2010 Long Term Incentive and Share Award Plan (the “Long Term Incentive Plan”). The Long Term Incentive Plan is intended to consolidate the Company’s long-term incentive compensation under a single plan, by replacing the Option Plan, the Restricted Plan and the 1992 Directors Share Option Plan (the “Directors Plan”) going forward, and to provide a more current set of terms pursuant to which to provide this type of compensation. The Long Term Incentive Plan is described in greater detail below under the heading “Description of Long Term Incentive Plan.”

Annex 2

Cash Bonus Plans.

CICP.     In 2004, the Compensation Committee, the Board and the shareholders approved the CEO Incentive Compensation Plan (the “CICP”) in order to make the Chief Executive Officer’s (“CEO”) compensation more commensurate with that of industry peers and because the Compensation Committee believed that it was not appropriate to include the CEO in the Management Incentive Compensation Plan given the CEO’s active role in administering that plan.

Only our CEO is eligible to participate in the CICP and, depending on his or her performance and that of the Company, earn incentive compensation. As soon as practicable after the end of each fiscal year (the “Plan Period”), the Compensation Committee recommends to the Board and the Board determines whether and to what extent certain pre-established Company objectives for that Plan Period (“Company Objectives”) have been met, each Company Objective having been assigned a percentage toward completion of the Company Objectives overall (each, a “Achievement Percentage”). For each Plan Period, unless 70% of the Company Objectives for that Plan Period have been met, no incentive compensation will be awarded. The Board retains considerable discretion both in determining the extent to which the Company Objectives are achieved and in considering additional factors which may influence its overall determinations.

The incentive compensation under the CICP is weighted based 70% on meeting Company Objectives and 30% based on a discretionary objectivesevaluation by the Compensation Committee. The award opportunity range for the CEO expressed as a percentage of his or her base salary is as follows: minimum award opportunity—25%; target award opportunity—50%; and maximum award opportunity—75%, in each case, of base salary.

The performance of the CEO is typically rated as soon as practicable following the conclusion of the Plan Period. Distribution of incentive compensation is generally made in February or March of the succeeding year after the Plan Period. The incentive awards granted under the CICP are payable in cash.

MICP .    Certain employees are also compensated through the Management Incentive Compensation Plan (the “MICP”), in which officers (other than the CEO) and employees who have the title of Senior Director, Director or Manager, as well as certain additional discretionary participants chosen by the CEO, are eligible to participate. Under the MICP, at the beginning of each Plan Period, the Board (with advice from the Compensation Committee) establishes a target incentive compensation pool, which is then adjusted at year-end to reflect the Company’s performance in achieving the Company Objectives.

After each Plan Period, the Board, based on the recommendation of the Compensation Committee, makes a determination as to the performance of the Company and MICP participants in meeting the Company Objectives and individual objectives for that Plan Period, which are determined from time to time by the Board in its sole discretion. Awards to MICP participants vary depending upon the level of achievement of the Company Objectives, the size of the incentive compensation pool and the MICP participants’ base salaries and performance during the Plan Period as well as their expected ongoing contribution to the Company. The Company must meet a minimum percentage of the Company Objectives (currently 70%) for a particular Plan Period before any awards are made under the MICP for that Plan Period. The Board retains considerable discretion both in determining the extent to which the Company Objectives are achieved and in considering additional factors which may influence its overall determinations.

For officers, including the executive officers named in the “Summary Compensation Table” below other than Mr. Engle, the incentive compensation under the MICP is weighted based 50% on meeting Company Objectives and 50, 30% based on individual and performance objectives and 20% based on a discretionary evaluation by the CEO. The target award for these officers as a percentage of base salary is 30%, with an award opportunity range of 15% to 45% of base salary. For other MICP participants, the incentive compensation is weighted based either 40% or 30% on meeting Company Objectives and, either 6040% or 70% based50% on individual and performance objectives and, in all cases, 20% on a discretionary evaluation by the CEO. The award opportunities for these participants as a percentage of base salary range from a minimum of 5% to a maximum of 37.5% of base salary, depending on among other things the participants’ position within the Company.

The performance of the MICP participants is typically rated as soon as practicable following the conclusion of the Plan Period. Distribution of incentive compensation is generally made in February or March of the succeeding year after the Plan Period. Awards under the MICP are payable in cash.

For 2009, 146 individuals were determined to be eligible to participate in the MICP, including all of the executive officers named in the “Summary Compensation Table” below other than Mr. Engle.

BCP .    Employees who are not eligible to participate in the CICP or the MICP are also compensated through the Bonus Compensation Plan (the “BCP”). Under the BCP, at the beginning of each Plan Period, the Board (with advice from the Compensation Committee) establishes a target incentive compensation pool, which is then adjusted at year-end to reflect the Company’s performance in achieving the Company Objectives.

After each Plan Period, the Board, based on the recommendation of the Compensation Committee, makes a determination as to the performance of the Company and BCP participants in meeting the Company Objectives, which are determined from time to time by the Board in its sole discretion. Awards to BCP participants vary depending upon the level of achievement of the Company Objectives, the size of the incentive compensation pool and the BCP participants’ base salaries. The Company must meet a minimum percentage of the Company Objectives (currently 70%) before any awards are made under the BCP. Awards under the BCP are payable in cash.

For 2009, 69 individuals were determined to be eligible to participate in the BCP.

Company ObjectivesBonus Determinations for 2009.     For 2009, the Compensation Committee recommended and the Board approved the following Company Objectives: (1) generate $20 to 25 million in cash in the first half of 2009, which was assigned a 40% Achievement Percentage, (2) enter into a significantly beneficial corporate partnership with respect to the Company’s lead product candidate, XOMA 052, by the end of 2009, which was assigned a 30% Achievement Percentage, (3) enter into technology licensing and/or collaboration transactions yielding at least a specified amount in upfront payments to the Company by the end of 2009, which was assigned a 15% Achievement Percentage, and (4) consolidate certain manufacturing operations, maintain certain manufacturing capacity and increase biodefense revenues, which was assigned a 15% Achievement Percentage. In February of 2010, the Board determined that the first such Company Objective had been exceeded, that the third and fourth such Company Objectives had been achieved and that the second such Company Objective had not been completed as of the end of 2009.

The Board, exercising its discretion, also took into account management’s performance in response to the severe adverse conditions and events affecting the Company in 2009, including general economic declines and market instability, the sudden withdrawal of RAPTIVA ® , in which the Company had a royalty interest, from the worldwide markets and the resulting threat of default under the Company’s loan from Goldman Sachs Specialty Holdings, Inc. (“Goldman Sachs”), which had been secured by such royalty interest, as well as other achievements during the Plan Period, including the removal of the “going concern” qualification from the opinion of the Company’s outside auditors regarding its 2008 financial statements, the sale of the Company’s royalty interest in LUCENTIS ® for $25 million, the Company’s successful organizational restructuring and certain aspects of its financial performance for the Plan Period. The Board also noted that, in the previous year, management had recommended, and the Board had determined, not to award bonuses under either the CICP or the MICP with respect to 2008 in light of economic conditions affecting the Company and in order to conserve its cash resources, notwithstanding that the Company had met a percentage of the Company Objectives for 2008 in excess of the minimum required. After evaluating the various facts and circumstances described above, the Board concluded that in excess of 100% of the Company Objectives had been achieved for the 2009 Plan Period.  As a result, the CEO and each of the other named executive officers received in excess of the target amounts attributable to achievement

CORRESP
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[On Cahill Gordon & Reindel llp Letterhead]

(212) 701-3265

November 16, 2010

Re:

XOMA Ltd.

Form 10-K for the Fiscal Year Ended December 31, 2009

Filed March 11, 2010

Form 10-K/A filed April 30, 2010

File No. 000-14710

Dear Mr. Riedler:

On behalf of XOMA Ltd. (the “Company”) and as discussed by telephone on November 16, 2010 with Laura Crotty, we have requested an extension of time to reply to your letter dated October 20, 2010 to Mr. Steven B. Engle of the Company, regarding the above-referenced report, until November 24, 2010.  Per my telephone conversation on November 16, 2010 with Ms. Crotty, our request for an extension until November 24, 2010 was granted.

The Company appreciates the Staff’s consideration.  The Company continues to diligently prepare a response.

Please direct any questions or concerns regarding this request to the undersigned at the number indicated above.  Thank you for your attention.

                Sincerely,

                /s/ Kimberly C. Petillo

                Kimberly C. Petillo

Jeffrey P. Riedler

Assistant Director

Division of Corporation Finance

United States Securities and Exchange Commission

100 F. Street, N.E.

Washington, D.C.  20549

VIA ELECTRONIC TRANSMISSION/BY HAND

cc:

Laura Crotty

Christopher J. Margolin

Geoffrey E. Liebmann

CORRESP
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    correspondence.htm

[Cahill Gordon & Reindel llp Letterhead]

(212) 701-3265

November 1, 2010

Re:

XOMA Ltd.

Form 10-K for the Fiscal Year Ended December 31, 2009

Filed March 11, 2010

Form 10-K/A filed April 30, 2010

File No. 000-14710

Dear Mr. Riedler:

On behalf of XOMA Ltd. (the “Company”) and as discussed by telephone on October 29, 2010 with Laura Crotty, we have requested an extension of time to reply to your letter dated October 20, 2010 to Mr. Steven B. Engle of the Company, regarding the above-referenced report, until November 17, 2010.  Per my telephone conversation on October 29, 2010 with Ms. Crotty, our request for an extension until November 17, 2010 was granted.

The Company appreciates the Staff’s consideration.  The Company continues to diligently prepare a response.

Please direct any questions or concerns regarding this request to the undersigned at the number indicated above.  Thank you for your attention.

                Sincerely,

                /s/ Kimberly C. Petillo

                Kimberly C. Petillo

Jeffrey P. Riedler

Assistant Director

Division of Corporation Finance

United States Securities and Exchange Commission

100 F. Street, N.E.

Washington, D.C.  20549

VIA ELECTRONIC TRANSMISSION/BY HAND

cc:

Laura Crotty

Christopher J. Margolin

Geoffrey E. Liebmann

October 20, 2010
 Steven B. Engle Chairman, Chief Executive Officer and President XOMA Ltd. 2910 Seventh Street Berkeley, California 94710
 Re: XOMA Ltd.
 Form 10-K for the Fiscal Year Ended December 31, 2009
  Filed March 11, 2010
  Form 10-K/A filed April 30, 2010   File No. 000-14710

 Dear Mr. Engle:

We have reviewed your October 5, 2010 response to our September 21, 2010
comment letter and have the following additiona l comments.  In some of our comments, we
may ask you to provide us with informati on so we may better understand your disclosure.
  Please respond to this letter within ten business days by providing the requested
information or by advising us when you will provide the requested response.  If you do not believe our comments apply to your facts and circumstances please tell us why in your
response.    After reviewing the information you provide  in response to these comments, we may
have additional comments.

Compensation Components

1. We note your response to our prior comment 3 and we resissue the comment.  Please
further revise the provided draft disclosure  to discuss the actual long-term incentive
award made to each named executive o fficer for the 2009 fiscal year and the
conclusions reached by the compensation committee in determining each award.
Your disclosure should discuss how each factor considered by the committee was evaluated or measured and how  the totality of the factors resulted in the long-term
incentive award made to each named executive officer.

Cash Bonus Plans

2. We note your response to our prior comment  4.  Please further revise the provided
draft disclosure to discuss the “indivi dual and performance objectives” referenced
throughout your discussion of the Manageme nt Incentive Compensation Plan.  Your
discussion should include not only the objectives themselves  but also the extent to
which each objective was achieved and how su ch level of achievement affected the
actual bonus awarded to each na med executive officer.

Steven B. Engle
XOMA Ltd. October 20, 2010 Page 2
We urge all persons who are responsible for the accuracy and adequacy of the
disclosure in the filing to be certain that the filing includes the information the Securities
Exchange Act of 1934 and all applicable Exchan ge Act rules require.  Since the company and
its management are in possession of all facts relating to a co mpany’s disclosure, they are
responsible for the accuracy and adequacy of the disclosures they have made.

In responding to our comments, please provi de a written statement from the company
acknowledging that:
• the company is responsible for the adequacy  and accuracy of the disclosure in the
filing;
• staff comments or changes to disclosure  in response to staff comments do not
foreclose the Commission from taking any action with respect to the filing; and
• the company may not assert staff comments as a defense in any proceeding initiated
by the Commission or any person under the federal securities laws of the United States.

Please contact Laura Crotty at (202) 551- 3563 or myself at (2 02) 551-3715 with any
questions.

 Sincerely,

 Jeffrey P. Riedler  Assistant Director
cc:  Kimberly C. Petillo (Cahill Gordon & Reindel LLP)

CORRESP
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[LETTERHEAD OF CAHILL GORDON & REINDEL LLP]

(212) 701-3265

October 5, 2010

Re:

XOMA Ltd.

Form 10-K for the Fiscal Year Ended December 31, 2009

Filed March 11, 2010

Form 10-K/A filed April 30, 2010

File No. 000-14710

Dear Mr. Riedler:

On behalf of and as counsel to XOMA Ltd. (the “Company”), we are responding to your letter dated September 21, 2010 (the “Comment Letter”) relating to the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2009 (the “Form 10-K”), filed with the Securities and Exchange Commission (the “SEC”) on March 11, 2010, and Amendment No. 1 on Form 10-K/A filed with the SEC on April 30, 2010 (the “Form 10-K/A”) (File No. 000-14710).

For your convenience, the Company’s responses below are numbered to correspond to the comments in the Comment Letter (the “Comments”).

Form 10-K for the fiscal year ended December 31, 2009

Item 1. Business, page 1

General

Comment No. 1:  We note your discussion throughout the Business section of various material license and collaboration agreements with third parties.  Please provide draft disclosure to be included in an amended Form 10-K quantifying the total potential milestone payments due under each agreement to the extent not already disclosed, a range of royalties to be paid within a ten percent range, and the duration and termination provisions of each.

Response No. 1:  Attached to this letter as Annex 1 is draft disclosure to be included in a further amendment to the Form 10-K in response to this Comment.

Signatures, page 71

Comment No. 2:  We note that your chief executive officer and chief financial officer have signed the Form 10-K on behalf of the registrant and in their own capacities, but it does not appear that the filing has not been signed by your controller or principal accounting officer in those capacities as required by Form 10-K.  Please ensure that your amendment to the Form 10-K includes the signature of the person acting in such capacity, as required by Instruction D.2(a) of Form 10-K.

Response No. 2:  The Company’s Vice President, Finance and Chief Financial Officer also acts as principal accounting officer.  Any further amendment to the Form 10-K will clarify that he is also signing in this additional capacity.

Form 10-K/A filed April 30, 2010

Compensation Components, page 5

Comment No. 3:  We note your disclosure regarding your long-term incentive program on page 5 of the filing.  Please provide draft disclosure to be included in an amended Form 10-K discussing the actual award made to each named executive officer for the 2009 fiscal year and the conclusions reached by the compensation committee in determining each award.  For instance, you note the factors considered by the committee.  Your disclosure should discuss how each factor was evaluated or measured and how the totality of the factors resulted in the award made to each named executive officer.

Response No. 3:  Attached to this letter as Annex 2 is revised disclosure, taken from the Company’s definitive proxy statement on Schedule 14A filed with the SEC on June 9, 2010 and marked to show changes from the corresponding sections in the Form 10-K/A, which we believe addresses the staff’s concerns as expressed in this Comment.

Comment No. 4:  We note your disclosure regarding the CEO Incentive Compensation Plan and Management Incentive Compensation Plan on pages 5 and 6 of the filing.  Please provide draft disclosure to be included in an amended Form 10-K which discusses the following information:

·

the “discretionary” and “individual” objectives referenced in the first and fifth paragraphs on page 6;

·

the level of achievement of each objective;

·

how such level of achievement translated into the awards made to each named executive officer on an individual basis;

·

the amount of the target incentive compensation pool and how such pool was adjusted at year-end to reflect the company’s performance in achieving its corporate objectives; and

-2-

·

any other factors considered by the committee that impacted the amount of incentive compensation awarded to the named executive officers.

Response No. 4:  Attached to this letter as Annex 2 is revised disclosure, taken from the Company’s definitive proxy statement filed with the SEC on June 9, 2010 and marked to show changes from the corresponding sections in the Form 10-K/A, which we believe addresses the staff’s concerns as expressed in this Comment.

Compensation Risk Assessment, page 7

Comment No. 5:  We note your disclosure in response to Item 402(s) of Regulation S-K on page 7 of the filing.  Please describe the process you undertook to reach your conclusion and provide an analysis supporting your determination that your compensation policies and practices are not reasonably likely to have a material adverse effect on the company.

Response No. 5:  The Company has advised us that, in order to determine whether risks arising from the Company’s compensation policies and practices for its employees are likely to have a material adverse effect on the Company, the Compensation Committee of the Company’s Board of Directors (the “Compensation Committee”), with the assistance of its independent compensation consultant, carefully reviewed and analyzed each element of employee compensation and determined the following: (1) significant weighting toward long-term incentive compensation discourages short-term risk-taking, (2) goals are appropriately set to avoid undue reliance on targets that, if not achieved, could result in a large percentage loss of compensation, (3) incentive awards are capped by the Compensation Committee, (4) compensation decisions include subjective considerations, described in the Compensation Disclosure and Analysis, which limit the influence of formulas or objective factors on excessive risk-taking, and (5) as a development-stage biopharmaceutical company, the Company does not face the same level of risks associated with compensation for employees at financial services companies, such as those related to traders who deal in high-risk financial instruments.  In light of the foregoing, the Compensation Committee concluded that its analysis supported the conclusions described in the Form 10-K/A.

Employment Contracts and Termination of Employment and Change of Control Arrangements, page 14

Comment No. 6:  We note that you have filed a form of employment agreement as Exhibit 10.7 to the filing.  Please also file each named executive officer’s executed employment agreement as an exhibit to the filing.

Response No. 6:  As requested, the Company will file each named executive officer’s executed employment agreement as an exhibit to a further amendment to the Form 10-K.

-3-

In addition, the Company acknowledges that:

·

the Company is responsible for the adequacy and accuracy of the disclosure in the filing;

·

staff comments or changes to disclosure in response to staff comments do not foreclose the Commission from taking any action with respect to the filing; and

·

the Company may not assert staff comments as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

The Company believes that the response set forth above is responsive to the Comment.  Please direct any questions or further comments regarding this filing to the undersigned at the number indicated above.

Sincerely,

/s/ Kimberly C. Petillo

Kimberly C. Petillo

Jeffrey Riedler

Assistant Director

Division of Corporation Finance

Securities and Exchange Commission

100 F Street, N.E.

Washington, D.C.  20549

VIA ELECTRONIC TRANSMISSION/BY HAND

cc:

Laura Crotty

Christopher J. Margolin

Geoffrey E. Liebmann

-4-

Annex 1

PART I

Item 1.

Business

*           *           *

Royalties and Technology Licenses

*           *           *

Technology Licenses

Below is a summary of certain proprietary technologies owned by us and available for licensing to other companies:

·

Antibody discovery technologies: XOMA uses human antibody phage display libraries in its discovery of therapeutic candidates, and we offer access to multiple libraries, including novel libraries developed internally, as part of our collaboration business. We believe that access to multiple libraries offers a number of benefits to XOMA and its partners, because it enables use of libraries best suited to the needs of a particular discovery project to increase the probability of technical and business success in finding rare and unique functional antibodies directed to targets of interest.

In 2009, we recognized $42.3 million in revenue related to the licensing of our antibody discovery technologies. In February of 2009, we expanded our existing collaboration with Takeda to provide Takeda with access to multiple antibody discovery technologies for a $29 million expansion fee, before taxes and other costs. In addition, in the second half of 2009, we entered into antibody discovery collaborations with Arana Therapeutics Limited, a wholly-owned subsidiary of Cephalon, Inc. (“Arana”), and The Chemo-Sero-Therapeutic Research Institute, a Japanese research foundation known as Kaketsuken, involving multiple proprietary XOMA antibody research and development technologies for fees of $6 million and $8 million, respectively. We may be entitled to future milestone payments and royalties on product sales related to the antibody discovery collaborations.

·

Bacterial Cell Expression: The production or expression of antibodies using bacteria is an enabling technology for the discovery and selection, as well as the development and manufacture, of recombinant protein pharmaceuticals, including diagnostic and therapeutic antibodies for commercial purposes. Genetically engineered bacteria are used in the recombinant expression of target proteins for biopharmaceutical research and development. Reasons include the relative simplicity of gene expression in bacteria as well as many years of experience culturing such species as E. coli in laboratories and manufacturing facilities. In support of our own biopharmaceutical development efforts, XOMA scientists have developed bacterial expression technologies for producing antibodies and other recombinant protein products.

We have granted over 50 licenses to biotechnology and pharmaceutical companies to use our patented and proprietary technologies relating to bacterial expression of recombinant pharmaceutical products. Bacterial antibody expression is also a key technology used in multiple systems for high-throughput screening of antibody domains. Expression of antibodies by phage display technology, for example, depends upon the expression and secretion of antibody domains from bacteria as properly folded, functional proteins.

Many licensees of our bacterial cell expression technology have developed, or are in the process of developing, antibodies for which we may be entitled to future milestone payments and royalties on product sales. Under the terms of our license agreement with Pfizer, signed in 2007, we received an up-front cash payment of $30 million and from 2008 through 2009 we received four milestone payments relating to four undisclosed product candidates, including a payment of $0.5 million for the initiation of a Phase 3 clinical trial. We aremay also be eligible for additional milestone, royalty and other fees payments aggregating up to $4.9 million relating to these four product candidates and low

single-digit royalties on future sales of all products subject to this license. In addition, we may receive potential milestone payments aggregating up to $1.7 million for each additional qualifying product candidate. Our right to milestone payments expires  on the later of the expiration of the last-to-expire licensed patent or the tenth anniversary of the effective date. Our right to royalties expires upon the expiration of the last-to-expire licensed patent.

Current licensees include but are not limited to the following companies:

Active Biotech AB

Crucell Holland B.V.

Novartis AG

Affimed Therapeutics AG

Dompe, s.p.a.

Pfizer, Inc.

Affitech AS

Dyax Corp.

Schering Corporation (now a

subsidiary of Merck & Co., Inc.)

Alexion Pharmaceuticals, Inc.

E.I. duPont de Nemours and

Company

Takeda Pharmaceutical Company Ltd.

Applied Molecular Evolution, Inc.

(now a subsidiary of Eli Lilly and

Company)

Eli Lilly and Company

The Medical Research Council

Avecia Limited

Genentech, Inc. (now a member of

the Roche Group)

UCB S.A.

Aventis Pharma Deutschland GmbH

(Hoechst) (now Sanofi-Aventis)

Invitrogen Corporation

Unilever plc

Bayer Healthcare AG

Merck & Co., Inc.

Verenium Corporation

BioInvent International AB

Mitsubishi Tanabe Pharma

Corporation

Wyeth Pharmaceuticals Division (now

a member of Pfizer, Inc.)

Centocor, Inc.

MorphoSys AG

ZymoGenetics, Inc.

These licenses are sometimes associated with broader agreements which may include expanded license rights, cell line development and process development.

·

Human Engineering™: Human Engineering™ is a proprietary technology that allows modification of non-human monoclonal antibodies to reduce or eliminate detectable immunogenicity and make them suitable for medical purposes in humans. The technology uses a unique method developed by us, based on analysis of the conserved structure-function relationships among antibodies. The method defines which residues in a non-human variable region are candidates to be modified. The result is a Human Engineered™ antibody with preserved antigen binding, structure and function, and with eliminated or greatly reduced immunogenicity. Human Engineering™ technology is used in development of XOMA 052 and certain other antibody products.

·

Targeted Affinity Enhancement™ (TAE): TAE is a proprietary technology involving the assessment and guided substitution of amino acids in antibody variable regions, enabling efficient optimization of antibody binding affinity and selectivity modulation. TAE generates a comprehensive map of the effects of amino acid mutations likely to impact binding. The technology is utilized by XOMA scientists and has been licensed to a number of our collaborators.

We also have access to certain intellectual property rights and services that augment our existing integrated antibody technology platform and development capabilities and further compress product development timelines. This broad antibody technology platform and expertise is available for building our antibody product pipeline as well as those of our collaborators.

-2-

*           *           *

Financial and Legal Arrangements of Product Collaborations, Licensing and Other Arrangements

Current Agreements

Takeda

In November of 2006, we entered into a fully funded collaboration agreement with Takeda for therapeutic monoclonal antibody discovery and development. Under the agreement, we will discover and optimize therapeutic antibodies against multiple targets selected by Takeda. Takeda will make up-front, annual maintenance and milestone payments to us, fund our research and development and manufacturing activities for preclinical and early clinical studies and pay royalties on sales of products resulting from the collaboration. Takeda will be responsible for clinical trials and commercialization of drugs after an IND submission and is granted the right to manufacture once a product enters into Phase 2 clinical trials. In the fourth quarter of 2009, certain discovery and development programs under this collaboration were discontinued following analysis of the research data. This resulted in the recognition of $2.8 million of the remaining unamortized balance in deferred revenue pertaining to the discontinued programs.

Under the terms of this agreement, we may receive potential milestone payments aggregating up to $20.75 million relating to one undisclosed product

September 21, 2010
 Steven B. Engle Chairman, Chief Executive Officer and President XOMA Ltd. 2910 Seventh Street Berkeley, California 94710
 Re: XOMA Ltd.
 Form 10-K for the Fiscal Year Ended December 31, 2009
  Filed March 11, 2010
  Form 10-K/A filed April 30, 2010   File No. 000-14710

 Dear Mr. Engle:

We have reviewed your filings and have the following comments.  In some of our
comments, we may ask you to provide us with  information so we may better understand your
disclosure.   Please respond to this letter within ten business days by providing the requested
information or by advising us when you will provide the requested response.  If you do not believe our comments apply to your facts and circumstances please tell us why in your
response.    After reviewing the information you provide  in response to these comments, we may
have additional comments.

Form 10-K for the fiscal year ended December 31, 2009
 Item 1. Business, page 1

 General

1. We note your discussion throughout  the Business section of various material license
and collaboration agreements with third partie s.  Please provide draft disclosure to be
included in an amended Form 10-K quan tifying the total potential milestone
payments due under each agreement to the extent not already di sclosed, a range of
royalties to be paid within a ten percen t range, and the duration and termination
provisions of each.
Signatures, page 71

2. We note that your chief executive officer a nd chief financial officer have signed the
Form 10-K on behalf of the registrant a nd in their own capacities, but it does not
appear that the filing has not been signed by your cont roller or principal accounting

Steven B. Engle
XOMA Ltd. September 21, 2010
Page 2
officer in those capacities as required by Form 10-K.  Please ensure that your
amendment to the Form 10-K includes the signature of the person acting in such
capacity, as required by Instructi on D.2(a) of Form 10-K.
 Form 10-K/A filed April 30, 2010

 Compensation Components, page 5

3. We note your disclosure regarding your long- term incentive program on page 5 of the
filing.  Please provide draft disclosure to  be included in an amended Form 10-K
discussing the actual award made to each na med executive officer for the 2009 fiscal
year and the conclusions reached by the compensation committee in determining each
award.  For instance, you note the factor s considered by the committee.  Your
disclosure should discuss how each factor was evaluated or measured and how the
totality of the factors resulte d in the award made to each named executive officer.

4. We note your disclosure regarding th e CEO Incentive Compensation Plan and
Management Incentive Compensation Plan on pages 5 and 6 of the filing.  Please provide draft disclosure to be included in  an amended Form 10-K which discusses the
following information:
• the “discretionary” and “individual” objectiv es referenced in the first and fifth
paragraphs on page 6;
• the level of achievement of each objective;
• how such level of achievement translated  into the awards made to each named
executive officer on an individual basis;
• the amount of the target incentive co mpensation pool and how such pool was
adjusted at year-end to reflect the company’s performance in achieving its corporate objectives; and
• any other factors considered by the committee that impacted the amount of
incentive compensation awarded to  the named executive officers.

Compensation Risk Assessment, page 7

5. We note your disclosure in response to It em 402(s) of Regulation S-K on page 7 of
the filing.  Please describe the process you undertook to reach your conclusion and
provide an analysis supporting your dete rmination that your compensation policies
and practices are not reasonably likely to have a material adverse effect on the
company.
 Employment Contracts and Termination of Employment and Change of Control
Arrangements, page 14

6. We note that you have filed a form of empl oyment agreement as Exhibit 10.7 to the
filing.  Please also file each named executive officer’s executed employment
agreement as an exhibit to the filing.

Steven B. Engle
XOMA Ltd. September 21, 2010 Page 3
We urge all persons who are responsible for the accuracy and adequacy of the
disclosure in the filing to be certain that the filing includes the information the Securities
Exchange Act of 1934 and all applicable Exchan ge Act rules require.  Since the company and
its management are in possession of all facts relating to a co mpany’s disclosure, they are
responsible for the accuracy and adequacy of the disclosures they have made.

In responding to our comments, please provi de a written statement from the company
acknowledging that:
• the company is responsible for the adequacy  and accuracy of the disclosure in the
filing;
• staff comments or changes to disclosure  in response to staff comments do not
foreclose the Commission from taking any action with respect to the filing; and
• the company may not assert staff comments as a defense in any proceeding initiated
by the Commission or any person under the federal securities laws of the United States.

Please contact Laura Crotty at (202) 551- 3563 or myself at (2 02) 551-3715 with any
questions.

 Sincerely,

 Jeffrey P. Riedler  Assistant Director

CORRESP
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    May 26, 2008

    Securities
and Exchange Commission

    100 F
Street, N.E.

    Washington,
D.C. 20549

              Attention:

              Rose
      Zukin

              Division
      of Corporation Finance

              Re:

              XOMA
      Ltd.

              Registration
      Statement on Form S-3

    File
No. 333-148342

    Filed
December 27, 2008, as amended May 19, 2008

    Ladies
and Gentlemen:

    Pursuant
to Rule 461 under the Securities Act of 1933, the undersigned, being the issuer
of securities to which the referenced Registration Statement relates,
respectfully requests that the effectiveness of the Registration Statement be
accelerated so that it will become effective at 2:00 P.M. on May 29, 2008 or as
soon thereafter as practicable.

    The
disclosure in the filing is the responsibility of XOMA Ltd. (the
“Company”).  The Company acknowledges that should the Commission or
the staff, acting pursuant to delegated authority, declare the filings
effective, it does not foreclose the Commission from taking any action with
respect to either filing.  The Company further acknowledges that the
action of the Commission or the staff, acting pursuant to delegated authority,
in declaring the filings effective, does not relieve the Company from its full
responsibility for the adequacy and accuracy of the disclosures in the
filings.

    The
Company represents to the Commission that it will not assert this action as a
defense in any proceeding initiated by the Commission or any person under the
federal securities laws of the United States.

              Very
      truly yours,

              XOMA
      Ltd.

              By:

            /s/
      Christopher J. Margolin

              Christopher
      J. Margolin

              Vice
      President, General

              Counsel
      and Secretary

Via Facsimile and U.S. Mail Mail Stop 6010                                                                                                  February 12, 2008
J. David Boyle II
Vice President, Finance and Chief Financial Officer
XOMA Ltd.
2910 Seventh Street
Berkeley, CA 94710

Re:   XOMA Ltd.
 Form 10-K for the Fiscal Year Ended December 31, 2006
 Filed March 8, 2007
 Form 10-Q for the Quarterly Period Ended September 30, 2007
 Filed November 8, 2007
 File Number:  000-14710

Dear Mr. Boyle:

 We have completed our review of your  above Forms 10-K and 10-Q and have no
further comments at this time.           S i n c e r e l y ,
Jim Atkinson
        A c c o u n t i n g  B r a n c h  C h i e f

CORRESP
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Securities and Exchange Commission Letter

 January 22, 2008

 Jim B. Rosenberg

 Senior Assistant Chief Accountant

 Division of Corporation Finance

 United States Securities and Exchange Commission

 Washington, D.C. 20549

 Mail Stop 6010

Re:
Comment Letter Dated November 19, 2007 to XOMA Ltd.

 Form 10-K for the Fiscal Year Ended December 31, 2006

 Form 10-Q for the Quarterly Period Ended September 30, 2007

 File No. 000-14710

 Dear Mr. Rosenberg:

 We refer to the follow-up questions we received via telephone on January 11, 2008 in relation to your comment letter dated November 19, 2007
(the “Comment Letter”), which sets forth the comments of the staff of the Securities and Exchange Commission (the “Staff”) regarding the Form 10-K for the year ended December 31, 2006 (the “2006 Form 10-K”) and the
Form 10-Q for the quarterly period ended September 30, 2007 of XOMA Ltd. (the “Company,” “we” or “us”).

 The follow-up
communication included two comments related to our response dated December 4, 2007 and pertains to the Company’s 2006 Form 10-K.

 Comment: We have read your response to Comment 2. Please confirm whether it is reasonably possible that any product candidates will be identified and therefore that the company will have to make milestone payments. If it is
reasonably possible, please confirm that you will include the amount of the potential milestone payments associated with those product candidates in the table of contractual obligations in your notes to the financial statements in future filings as
we believe that information would be useful to investors. Also clarify for us what the “typical” milestone stream is related to each indication that may be subject to the various agreements.

 Response: We confirm that it is reasonable that some product candidates will be identified and we may, at some point in the future, be required to make future
milestone payments. Accordingly, we intend to revise our footnote disclosure to the table of contractual obligations in future filings, beginning with our 2007 Form 10-K, to read substantially as follows:

 In addition to the above, we have committed to make potential future “milestone” payments to third parties as part of licensing and
development programs. Payments under these agreements become due and payable only upon the achievement of certain developmental, regulatory and/or commercial milestones. Because it is uncertain if and when these milestones will be achieved, such
contingencies, aggregating up to $XX, have not been recorded on our consolidated balance sheet. We are unable to determine precisely when and if our payment obligations under the agreements will become due as these obligations are based on milestone
events, the achievement of which is subject to a significant number of risks and uncertainties.

 Further, we are unable to provide a “typical” milestone stream as historically our contracts contain terms
specific to and customized for each partner. Milestone payments per our existing contracts vary from as little as $10,000 to as much as $3.0 million.

 Comment: Refer to your response to Comment 4. Please clarify in your proposed disclosure that any adjustments to the revenues recognized in any given period are adjusted on a prospective basis and therefore would never result in the
reversal of revenues should the estimate to complete be extended.

 Response: We intend to revise our future filings, beginning with our 2007 Form
10-K, to reflect substantially the following language regarding contract revenue:

 Contract revenue for research and development involves
the Company providing research and development and contract manufacturing services to collaborative partners or others. Revenues for certain contracts are accounted for by a proportional performance, or output based, method where performance is
based on estimated progress made toward elements defined in the contract. The Company recognizes revenue under these arrangements as the related research and development costs are incurred and collectibility is reasonably assured. The amount of
contract revenue and related costs recognized in each accounting period are based on management’s estimates of the proportional performance during the period towards elements defined in the contract. Adjustments to management’s estimates
based on actual performance are recognized on a prospective basis and do not result in reversal of revenues should the estimate to complete be extended.

 If you have any further questions regarding this letter, please do not hesitate to contact me at (510) 204-7234.

Sincerely yours,

XOMA Ltd.

/s/ J. David Boyle II

J. David Boyle II

Vice President, Finance and Chief Financial Officer

Mail Stop 6010         January 3, 2008   Christopher J. Margolin, Esq. XOMA Ltd. 2910 Seventh Street Berkeley, CA  94710
Re: XOMA Ltd.
 Registration Statement on Form S-3
Filed December 26, 2007
 File Number 333-148342
Dear Mr. Margolin:

We have reviewed your filing and have the fo llowing comments.  Where indicated, we think
you should revise your document in response to this comment.  If you disagree, we will consider your
explanation as to why our comment is inapplicable or  a revision is unnecessary.  Please be as detailed
as necessary in your explanation.

Form S-3

1. Please file forms of your indentures as exhi bits to the registration statement prior to
requesting effectiveness.  As you may be aware, the Trust Indenture Act of 1939 requires that
an indenture be qualified at  the time of registration.

In addition, we issued comments under separa te cover on your Form 10-K annual report for
fiscal year ended December 31, 2006, and we will be monitoring your registration statement for
clearance of these comments.  All co mments will need to be fully resolved before we take final action
on the registration statement.
* * *

  We urge all persons who are responsible for th e accuracy and adequacy of the disclosure in
the filings reviewed by the staff to be certain that they have provided all information investors require for an informed decision.  Since the company and its management are in possession of all facts relating to a company’s disclosure, they are re sponsible for the accuracy and adequacy of the
disclosures they have made.

Christopher J. Margolin, Esq.
XOMA Ltd. January 3, 2008 Page 2
 Notwithstanding our comments, in the even t the company requests acceleration of the
effective date of the pending registration statement,  it should furnish a letter, at the time of such
request, acknowledging that:

• should the Commission or the staff, acting pursua nt to delegated authority, declare the filing
effective, it does not foreclose the Commission from taking any action with respect to the
filing;

• the action of the Commission or the staff, acting pursuant to delegated authority, in declaring
the filing effective, does not re lieve the company from its full responsibility for the adequacy
and accuracy of the disclosure in the filing; and

• the company may not assert this action as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.
 In addition, please be advised th at the Division of Enforcement has access to all information
you provide to the staff of the Divi sion of Corporation Finance in c onnection with our review of your
filing or in response to our comments on your filing.   We will consider a written request for acceleration of the effective date of the registration statement as a confirmation of the fact that those requesting acceleration are aw are of their respective
responsibilities under the Securities Act of 1933 and the Securities Exchange Act of 1934 as they
relate to the proposed public offeri ng of the securities sp ecified in the above registration statement.
We will act on the request and, pursuant to delegate d authority, grant acceleration of the effective
date.    Please contact Rose Zukin at (202) 551-3239 or me at (202) 551-3710 with any questions.
        S i n c e r e l y ,

        J e f f r e y  P .  R i e d l e r         A s s i s t a n t  D i r e c t o r    cc: Geoffrey E. Liebmann, Esq.  Cahill Gordon & Reindel LLP  80 Pine Street  New York, NY 10005

CORRESP
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Correspondence Letter

 XOMA Ltd.

 2910 Seventh Street

 Berkeley, California 94710

 December 4, 2007

 Securities and Exchange Commission

 Washington, D.C. 20549

 Ladies and Gentlemen:

 Pursuant to Mr. Rosenberg’s Comment Letter to our CEO, Steven B. Engle dated November 19, 2007, we are submitting the following response regarding the
Form 10-K for the year ended December 31, 2006 and the Form 10-Q for the quarterly period ended September 30, 2007 for File No. 000-14710.

 The
Comment Letter contains six comments related to the Company’s 2006 Form 10-K, which are numbered one to six in your letter, respectively, and one comment related to the Company’s third quarter 2007 Form 10-Q, which is numbered seven in
your letter. Our responses attached use the same numbering to assist the Staff in their review.

Sincerely,

XOMA Ltd.

/s/ J. David Boyle II

J. David Boyle II

Vice President, Finance and Chief Financial Officer

 December 4, 2007

 Jim B. Rosenberg

 Senior Assistant Chief Accountant

 Division of Corporation Finance

 United States Securities and Exchange Commission

 Washington, D.C. 20549

 Mail Stop 6010

Re:
Comment Letter Dated November 19, 2007 to XOMA Ltd.

 Form 10-K for the Fiscal Year Ended December 31, 2006

 Form 10-Q for the Quarterly Period Ended September 30, 2007

 File No. 000-14710

 Dear Mr. Rosenberg:

 We refer to your comment letter dated November 19, 2007 (the “Comment Letter”), which sets forth the comments of the staff of the
Securities and Exchange Commission (the “Staff”) regarding the Form 10-K for the year ended December 31, 2006 (the “2006 Form 10-K”) and the Form 10-Q for the quarterly period ended September 30, 2007 of XOMA Ltd. (the
“Company,” “we” or “us”).

 The Comment Letter contains six comments related to the Company’s 2006 Form 10-K, which are
numbered one to six in your letter, respectively, and one comment related to the Company’s third quarter 2007 Form 10-Q, which is numbered seven in your letter. Our responses below use the same numbering to assist the Staff in their review.

 Comments Related to the Form 10-K for the Fiscal Year Ended December 31, 2006

1.
Comment: The agreements with the following companies do not appear to be filed as exhibits: Lexicon, NIAID, Taligen, AVEO, Attenuon, and Triton. Please provide us with
an analysis supporting your determination that you are not substantially dependent on each of these agreements.

 Response: (1) With regard to the Company’s agreements with the National Institute of Allergy and Infectious Diseases (“NIAID”), these agreements have been filed with the Commission. We refer you to the
following exhibits listed in the Exhibit Index of the 2006 Form 10-K:

•

 10.45 Agreement dated July 28, 2006, between XOMA (US) LLC and the National Institute of Allergy and Infectious Diseases, which is incorporated by
reference to the referenced exhibit to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2006.

•

 10.53 Agreement dated March 8, 2005, between XOMA (US) LLC and the National Institute of Allergy and Infectious Diseases, which is incorporated by
reference to the referenced exhibit to the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2004.

 (2) With regard to the Company’s agreements with Lexicon, Taligen, AVEO, Attenuon,
and Triton, we conducted our analysis of whether we are required to file these agreements as exhibits to our Form 10-K in accordance with the subpart to Item 601(b)(10)(ii)(B) of Regulation S-K as follows:

 Lexicon – The agreement with Lexicon is a cost and revenue sharing and development collaboration agreement. We have not yet successfully
commercialized any product targets from this collaboration, and our costs incurred under this agreement were not material to our 2006 results. We currently estimate that this agreement will not become individually material to us in any past, current
or future period.

 Taligen – The agreement with Taligen is a process development and manufacturing agreement. The agreement
calls for Taligen to pay XOMA for development costs including a mark-up. The total potential revenue is forecast to be approximately $2.9 million over the contract life. We currently estimate that this agreement will not become individually material
to us in any past, current or future period.

 AVEO – The two agreements with AVEO are a process engineering agreement and a
development and manufacturing agreement. The engineering agreement provides the Company with an upfront payment of $25,000, annual payments of $30,000, and allows for potential future milestone payments of up to $7.15 million, in addition to
royalties on any future product sales. The development agreement calls for AVEO to pay XOMA for development costs, plus a mark-up, for potential revenue of $5.8 million over the contract life.

 Further, we have not yet successfully commercialized any product targets from these agreements, and our revenues and expenses under these agreements were
not material to our 2006 results. While these contracts represent significant potential revenue to the Company if certain milestones are reached and if the product target(s) are successfully commercialized, the Company does not believe it is
substantially dependent on these agreements or that the termination of either or both agreement would materially adversely affect the Company.

 Attenuon – The agreement with Attenuon is an engineering development agreement. The agreement provides the Company with an upfront payment of $35,000, annual payments ranging from $30,000 to $70,000, and allows for potential
future milestone payments of up to $6.06 million, in addition to royalties on any future product sales. We have not yet successfully commercialized any product targets from this agreement, and thus this agreement is not currently material to us. We
estimate that this agreement will not become individually material to us in any past, current or future period.

 Triton – The
agreement with Triton is a license and commercialization agreement. The agreement provides the Company with upfront payments of $250,000 and an optional $500,000 for study materials, and allows for potential future milestone payments of up to $1.9
million, in addition to royalties on any future product sales. We have not yet successfully commercialized any product targets from this agreement, and thus this agreement is not currently material to us. We currently estimate that this agreement
will not become individually material to us in any past, current or future period.

 Combined revenues from these agreements represented only 6.7% of revenue for the year ended
December 31, 2006 and 10.2% of revenue for the nine months ended September 30, 2007, as shown below (dollars in thousands):

 Revenue

Year Ended
December 31, 2007

Nine Months Ended,
September 30, 2007

 Combined revenue from Lexicon, Taligen, AVEO, Attenuon, and Triton

$
1,974

6.7
%

$
7,092

10.2
%

 All other companies

27,524

93.3
%

62,436

89.8
%

 Total as reported

$
29,498

100.0
%

$
69,528

100.0
%

 Based on the revenue as reported above, as well as management’s current estimates of the
potential future revenues and shared expenses to be recognized under each of these agreements, we have determined that each of these agreements is not material to the Company and thus the Company is not substantially dependent on any of the
aforementioned agreements.

 Based on the foregoing analysis, the Company has determined that none of these agreements are required to be
filed as Exhibits under Item 601 of Regulation S-K.

2.
Comment: Please revise your note to the table of contractual obligations to include the aggregate amount of potential milestone payments along with a description of
the events that would trigger these payments. Also explain to us why you do not include a discussion of these potential obligations in your financial statements.

 Response: For reference, the Company included the following footnote disclosure to the table of contractual obligations on page 49 of the
2006 Form 10-K.

 In addition to the above, we have committed to make potential future “milestone” payments to third parties as
part of licensing and development programs. Payments under these agreements generally become due and payable only upon the achievement of certain developmental, regulatory and/or commercial milestones. Because it is uncertain if and when these
milestones will be achieved, such contingencies have not been recorded on our consolidated balance sheet.

 In response to the
Staff’s comment, we note that the Company cannot reasonably estimate the aggregate amount of potential milestone agreements, as certain agreements contain milestones for each product candidate identified during the course of the related
development or collaboration agreement. The maximum potential payments will vary depending on the number of product candidates, which cannot be reasonably estimated as they are in the early stages of development and their potential approval cannot
be determined at this time. We have disclosed the existence of these obligations in the disclosure as noted above, in accordance with the guidance of Item 303(a)(5) of Regulation S-K.

 We also note that a description of the events that would trigger these payments has already been included
in the disclosures included on page 49 of the 2006 Form 10-K. Specifically, “payments under these agreements generally become due and payable only upon the achievement of certain developmental, regulatory and/or commercial milestones.” We
believe this disclosure captures each of the specific events that generally trigger the Company’s liability to make future milestone payments.

 Accordingly, we do not believe that it is necessary to amend the footnote disclosure referred to above in future filings to comply with the requirements of Item 303(a)(5).

 With regard to the Staff’s request for an explanation as to why we do not include a discussion of these potential obligations in our financial
statements, we have reviewed the nature of our potential obligations under these agreements and have determined that these obligations could be viewed as requiring disclosure based on SFAS No. 5, paragraphs 18-19, as a “commitment”
that we estimate is reasonably possible will be paid. As noted above, however, we are not able to indicate a range or maximum of potential milestone payments. Accordingly, in future filings, beginning with our 2007 Form 10-K, we intend to include in
the notes to our consolidated financial statements disclosure substantially similar to the disclosure in the MD&A section of our 2006 Form 10-K referred to above.

3.
Comment: Your CEO and CFO concluded that the “disclosure controls and procedures are effective in timely alerting them” to information that is required to be
disclosed. Your quarterly reports on Form 10-Q contain similar language. This conclusion does not appear to satisfy Item 307 of Regulation S-K and Rule 13a-15(e) under the Exchange Act. Rule 13a-15(e) states that disclosure controls and
procedures should ensure that information required to be disclosed “is recorded, processed, summarized and reported, within the time periods specified in the Commission’s rules and forms”. Please confirm that the disclosure controls
and procedures ensure that information required to be disclosed is recorded, processed, summarized and reported, within the time periods specified in the Commission’s rules and forms. If your are unable to confirm this statement,

•

 Please provide further explanation including a description of any weaknesses that prevented the CEO and CFO from concluding that the disclosure controls and
procedures were effective: and

•

 Amend the Form 10-K to describe the weaknesses.

 Response: We confirm that our evaluations of disclosure controls and procedures for the 2006 Form 10-K and the quarterly reports on Form 10-Q for the first, second and third quarters of 2007 were
conducted in accordance with the requirements of Item 307 of Regulation S-K and Rule 13a-15(e) under the Exchange Act. We further confirm that the disclosure controls and procedures for these respective periods were effective to ensure that
information required to be disclosed was recorded, processed, summarized and reported within the time periods specified in the Commission’s rules and forms.

 We note that for the 2006 Form 10-K, as stated in our original disclosures, “we conducted an
evaluation of our disclosure controls and procedures, as such term is defined under Rule 13a-15(e) promulgated under the Securities Exchange Act of 1934, as amended,” (emphasis added). We do recognize Staff’s
comment, however, that our conclusion as to the effectiveness of our disclosure controls and procedures did not specifically refer to the language of Rule 13a-15(e). Therefore, we intend to amend the language in our future filings, beginning with
our 2007 Form 10-K, to read substantially as follows:

 Under the supervision and with the participation of our management, including our
Chairman of the Board, Chief Executive Officer and President and our Vice President, Finance and Chief Financial Officer, we conducted an evaluation of our disclosure controls and procedures, as such term is defined under Rule 13a-15(e) promulgated
under the Securities Exchange Act of 1934, as amended, as of the end of the period covered by this report. Our disclosure controls and procedures are intended to ensure that the information we are required to disclose in the reports that we file or
submit under the Securities Exchange Act of 1934 is (i) recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission’s rules and forms and (ii) accumulated and
communicated to our management, including the Chairman of the Board, Chief Executive Officer and President and Vice President, Finance and Chief Financial Officer, as the principal executive and financial officers, respectively, to allow timely
decisions regarding required disclosures. Based on this evaluation, our Chairman of the Board, Chief Executive Officer and President and our Vice President, Finance and Chief Financial Officer concluded that our disclosure controls and procedures
were effective as of the end of the period covered by this report.

4.
Comment: Please explain to us why it is appropriate to recognize a “cumulative impact” instead of the change on a prospective basis related to this change in
estimate. Refer to paragraph 19 of SFAS 154.

 Response: We would like to clarify our use of the phrase
“cumulative impact,” as noted in the Staff comment, as such phrase is similar to the term “cumulative effect” used in paragraphs 7-9 of SFAS No. 154, which describes the appropriate accounting for changes in accounting
principle rather than our intended accounting for changes in estimate, which is governed by paragraph 19 of SFAS No. 154.

 Our use of
the phrase was intended to convey that for each reporting period, we update our estimate of progress made during the period for each agreement with contract revenue and related research and development costs. We account for contract revenue
agreements by a proportional performance, or output based, method where performance is based on the estimated progress made toward elements defined in the contract. We recognize revenue under these arrangements as the related research and
development costs are incurred and collectibility is reasonably assured. At the end of each period, we estimate our completion of the project based on services received by the customer and compare this to the cumulative progress recognized through
the end of the preceding period. This difference, which represents the progress we completed during the period, is the amount we recognize as revenue in each period (which we referred to as “cumulative impact”). We intended to co

Via Facsimile and U.S. Mail
Mail Stop 6010

         November 19, 2007

Steven B. Engle
President and Chief Executive Officer
XOMA Ltd.
2910 Seventh Street
Berkeley, CA 94710

Re:   XOMA Ltd.
 Form 10-K for the Fiscal Year Ended December 31, 2006
 Filed March 8, 2007
 Form 10-Q for the Quarterly Period Ended September 30, 2007
 Filed November 8, 2007
 File Number:  000-14710

Dear Mr. Engle:

We have reviewed your filings and have the following comments.  In our
comments, we ask you to provide us with  information to better understand your
disclosures.  Where a comment requests you to revise disclosure, the information you
provide should show us what the revised disc losure will look like and identify the annual
or quarterly filing, as appli cable, in which you intend to fi rst include it.  If you do not
believe that revised disclosure  is necessary, explain the reason in your response.  After
reviewing the information provided, we may raise additional comments and/or request
that you amend your filings.

 Please understand that the purpose of our re view process is to assist you in your
compliance with the applicable disclosure  requirements and to  enhance the overall
disclosure in your filings.  We look forward to working with you in these respects.  We
welcome any questions you may have about our  comments or on any other aspect of our
review.  Feel free to call us at the telephone numbers listed at the end of this letter.

Form 10-K for the fiscal year ended December 31, 2006
 Current Agreements, page 7

Steven B. Engle
XOMA Ltd. November 19, 2007 Page 2  1. The agreements with the following compan ies do not appear to be filed as
exhibits: Lexicon, NIAID, Taligen, AVE O, Attenuon, and Triton.  Please provide
us with an analysis supp orting your determination that  you are not substantially
dependent on each of these agreements.

Liquidity and Capital Resources, page 46

2. Please revise your note to the table of contractual obligations to include the
aggregate amount of potential milestone pa yments along with a description of the
events that would trigger these paymen ts.  Also explain to us why you do not
include a discussion of thes e potential obligations in your financial statements.

Item 9A. Controls and Procedures, page 53
3. Your CEO and CFO concluded that the “d isclosure controls and procedures are
effective in timely alerting them” to info rmation that is required to be disclosed.
Your interim Forms 10-Q contain simila r language.  This conclusion does not
appear to satisfy Item 307 of Regula tion S-K and Rule 13a-15(e) under the
Exchange Act.  Rule 13a-15(e) states th at disclosure controls and procedures
should ensure that information required to  be disclosed “is recorded, processed,
summarized and reported, within the time pe riods specified in the Commission’s
rules and forms.”  Please confirm that th e disclosure controls and procedures
ensure that information required to be disclosed is recorded, processed,
summarized and reported within the time periods specified in the Commission’s
rules and procedures.  If you are una ble to confirm this statement,

• Please provide further explanation incl uding a description of any weaknesses
that prevented the CEO and CFO from conc luding that the disclosure controls
and procedures were effective; and
• Amend the Form 10-K to describe the weaknesses.

Notes to Consolidated Financial Statements, page F-7
 1.  Business and Summary of Signifi cant Accounting Policies, page F-7

 Critical Accounting Policies, page F-7

 Contract Revenue, page F-8

4. Please explain to us why it is appropri ate to recognize a “cumulative impact”
instead of the change on a prospective basi s related to this change in estimate.
Refer to paragraph 19 of SFAS 154.

Steven B. Engle
XOMA Ltd. November 19, 2007 Page 3    3.  Collaborative and Licensing Agreements, page F-17

 Schering Plough, page F-19

5. Please explain to us why you  believe th at it was appropriate to recognize the
maintenance fees in this agreement as well as the Takeda agreement “when they
are due.”  Include a discussion of the natu re, extent and timing of your obligations
under the agreements associated  with these fees.  Refer to the specific paragraphs
within the applicable  authoritative literature upon wh ich you relied in determining
this treatment.

10. Subsequent Events, page F-30
6. Please clarify whether you have any re maining manufacturing obligations under
your agreement with Novartis.  If so, pleas e explain to us why it is appropriate to
recognize the entire $4.3 million in the first quarter of 2007.

Form 10-Q for the quarterly period ended September 30, 2007
 3. Collaborative And Other Arrangements, page 10

Other, page 10
7. We note the disclosure regarding an  August 13, 2007 restated and amended
license agreement with an ex isting technology partner.  Pl ease provide an analysis
supporting your determination that it wa s not necessary to file a Form 8-K
disclosing the amended agreement or file the agreement as an exhibit.

* * * *

 Please provide us the information request ed within 10 busine ss days or tell us
when you will provide us with a response.  Pl ease furnish a cover le tter with your response
that keys your response to our comments.  De tailed cover letters gr eatly facilitate our
review.  Please furnish your letter on EDGAR under the form type label CORRESP.

 We urge all persons who are responsible  for the accuracy and adequacy of the
disclosure in the filings to be certain that  the filings include all information required
under the Securities Exchange Act of 1934 and that they have provided all information
investors require for an informed invest ment decision.  Since the company and its
management are in possession of all facts re lating to a company’s disclosure, they are
responsible for the accuracy and adequacy of the disclosures they have made.

Steven B. Engle
XOMA Ltd. November 19, 2007 Page 4
 In connection with responding to our co mments, please provide, in your letter, a
statement from the company acknowledging that:

• the company is responsible for the adequacy and accuracy of the disclosure in
the filings;
• staff comments or changes to disclosure  in response to staff comments do not
foreclose the Commission from taking a ny action with respect to the filings;
and
• the company may not assert staff comme nts as a defense in any proceeding
initiated by the Commission or any pers on under the federal s ecurities laws of
the United States.

 In addition, please be advi sed that the Division of En forcement has access to all
information you provide to the staff of the Divi sion of Corporation Fi nance in our review
of your filings or in response to our comments on your filings.

Please contact Vanessa Robe rtson, Staff Accountant, at (202) 551-3649 or Jim
Atkinson, Accounting Branch Chief, at (202) 551-3674 if you have any questions
regarding the processing of your response as well as any questions regarding comments
on the financial statements and related matte rs.  You may contact Greg Belliston, Staff
Attorney, at (202) 551-3861 and Suzanne Haye s, Legal Branch Chief, at (202) 551-3675
with questions on any of the ot her comments.  In this regar d, do not hesitate to contact
me, at (202) 551-3679.

        S i n c e r e l y ,

        J i m  B .  R o s e n b e r g
Senior Assistant Chief
Accountant

Via Facsimile and U.S. Mail
Mail Stop 6010

August 15, 2006

John L. Castello
Chairman of the Board, President
and Chief Executive Officer
XOMA Ltd.
2910 Seventh Street
Berkeley, California 94710

Re: XOMA Ltd.
 Form 10-K for Fiscal Year Ended December 31, 2005
 Filed March 8, 2006
 File No. 000-14710

Dear Mr. Castello:

We have completed our review of your Form 10-K and have no further comments
at this time.

        S i n c e r e l y ,

        J i m  A t k i n s o n
        A c c o u n t i n g  B r a n c h  C h i e f

CORRESP
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      Xoma Response Letter - 04/10/06

    XOMA
      Ltd.

    2910
      Seventh Street

    Berkeley,
      California 94710

    VIA
      FACSIMILE AND EDGAR

    April
      10,
      2006

    Mr.
      Jim
      B. Rosenberg

    Senior
      Assistant Chief Accountant

    Securities
      and Exchange Commission

    Division
      of Corporate Finance

    100
      F
      Street, N.E.

    Mail
      Stop
      6010

    Washington,
      D.C. 20549

    Re:
      XOMA Ltd. (the “Company”)

      Form 10-K for the fiscal year ended December 31, 2005 (the “2005 Form
      10-K”)

      Filed March 8, 2006

      File No. 000-14710

    Dear
      Mr.
      Rosenberg:

    This
      letter will respond to your letter dated March 28, 2006 to John L. Castello,
      Chairman of the Board, President and Chief Executive Officer of the Company,
      regarding the staff’s comment relating to the 2005 Form 10-K. This letter sets
      forth the staff’s comment as set forth in your letter, followed by the Company’s
      response.

    Comment:

    Notes
      to Consolidated Financial Statements, page F-7

    1.
      Business and Summary of Critical Accounting Policies, page
      F-7

    Critical
      Accounting Policies, page F-8

    Contract
      Revenue, page F-9

    1.
      Please
      tell us why it is appropriate to recognize revenue on certain contracts using
      the percentage of completion method, as footnote 1 of SOP 81-1 states that
      SOP
      81-1 is not intended to apply to service transactions. In addition, please
      tell
      us why it is appropriate to recognize revenue as you progress towards, as
      opposed to upon completion of, the deliverables and milestones that your policy
      suggests are established in the contracts. In so doing, please tell us how
      the
      input measures used in that method are reasonable surrogates for the output
      measures established in the contracts and how your recognition complies with
      SAB
      104.

    Response:

    The
      particular contract at issue is one that XOMA entered into with the
      National Institute of Allergy and Infectious Diseases (NIAID), part of the
      National Institutes of Health,
      to
      produce three botulinum neurotoxin monoclonal antibodies designed to protect
      U.S. citizens against the harmful effects of biological agents used in
      bioterrorism. Under the 18-month
      agreement, XOMA is developing therapeutic
      products
      using
      proprietary antibody expression systems to produce anti-type A-botulinum
      neurotoxin monoclonal antibodies including a Master Cell Bank, Manufacturer’s
      Working Cell Bank and other designated deliverables detailed in Article C.1.
      -
      Statement of Work of the contract. The contract is available on EDGAR as Exhibit
      10.53 to the Company’s Annual Report on Form 10-K for the fiscal year ended
      December 31, 2004.

    Payments
      under the contract are not dependent upon achievement of “milestones” or
      specific deliverables but are based on agreed progress toward elements defined
      in the Statement of Work. The progress is agreed with NIAID based on monthly
      technical progress reports. We recognize revenue under this contract based
      on
      the proportional performance method, not the percentage of completion method.
      In
      response to the Staff’s comment, the Company will revise its future disclosure
      to clarify the revenue recognition method we are using for this contract.

    We
      have
      concluded that due to the nature of this contract
      the
      proportional performance method of revenue recognition is appropriate based
      on
      the following:

            ·

              XOMA
                is performing a service to NIAID’s
                specifications.

            ·

              The
                contract is a legally enforceable
                agreement.

            ·

              Performance
                extends over a long period.

            ·

              XOMA’s
                right to receive payment depends on agreed progress in accordance
                with the
                agreement.

            ·

              The
                contract services include development and manufacture of cGMP bulk
                drug
                substance for up to three human or human-compatible
                monoclonal
                antibodies (starting
                with material provided by NIAID).

    We
      determined that recognizing revenue using proportional performance or output
      based methodology was the most appropriate versus a cost based methodology
      implied by the percentage of completion methodology. The expected output
was
      the
      most appropriate basis because it is a reasonable dependable estimate of the
      revenue applicable to various contract elements. Output performance,
      as
      defined in the Statement of Work,
      is
      reviewed and discussed with NIAID on a monthly basis.

    We
      have
      reviewed this arrangement with respect to guidance from SAB 104 and determined
      that:
      persuasive evidence of an arrangement does exist as evidenced by the contract
      with NIAID;
      delivery
      has
      occurred and services have been rendered as evidenced by monthly technical
      progress updates discussed and agreed with NIAID;

    the
      price
      is fixed and determinable as evidenced by the contract fixed price of $15
      million;
      and
      collectibility is reasonably assured as evidenced by
      past
      receipt
      of regular payments
      and
      given
      that the customer is an agency of the US government.

    Based
      on
      the foregoing, we believe recognition of revenue under this contract using
      the
proportional
      performance method to be appropriate.

    *
      *           *

    In
      addition, the Company acknowledges that:

            ·

              the
                Company is responsible for the adequacy and accuracy of the disclosure
                in
                the filing;

            ·

              staff
                comments or changes to disclosure in response to staff comments do
                not
                foreclose the Commission from taking any action with respect to the
                filing; and

            ·

              the
                Company may not assert staff comments as a defense in any proceeding
                initiated by the Commission or any person under the federal securities
                laws of the United States.

    If
      you
      have any further questions, please do not hesitate to contact me at (510)
      204-7234. Thank you for your time and attention.

    Very
      truly yours,

    /s/
      J.
      DAVID BOYLE II

    J.
      David
      Boyle II

    Vice
      President, Finance and Chief Financial Officer

    cc:
      James
      Peklenk

    Oscar
      M.
      Young

    John
      L.
      Castello

    Christopher
      J. Margolin

    Candileigh
      Monzo

    Geoffrey
      E. Liebmann

Via Facsimile and U.S. Mail
Mail Stop 6010

                                                                                                March 28, 2006

John L. Castello
Chairman of the Board, President
and Chief Executive Officer
XOMA Ltd.
2910 Seventh Street
Berkeley, California 94710

Re: XOMA Ltd.
 Form 10-K for Fiscal Year Ended December 31, 2005
 Filed March 8, 2006
 File No. 000-14710

Dear Mr. Castello:

We have limited our review of your filing to the issue we have addressed in our
comment.  In our comment, we ask you to provi de us with information so we may better
understand your disclosure.  Please be as detail ed as necessary in your explanation.  After
reviewing this information, we may raise additional comments.

 Please understand that the purpose of our re view process is to assist you in your
compliance with the applicable disclosure  requirements and to  enhance the overall
disclosure in your filings.  We look forward to working with you in these respects.  We
welcome any questions you may have about our comment or on any other aspect of our
review.  Feel free to call us at the telephone numbers listed at the end of this letter.

Notes To Consolidated Financial Statements, page F-7

1.   Business and Summary of Signi ficant Accounting Policies, page F-7

Critical Accounting Policies, page F-8

Contract Revenue, page F-9

1. Please tell us why it is appropriate to recognize revenue on certain contracts using
the percentage of completion method, as f ootnote 1 of SOP 81-1 states that SOP
81-1 is not intended to apply to service transactions.  In a ddition, please tell us

John L. Castello
XOMA Ltd.
March 28, 2006
Page 2

why it is appropriate to r ecognize revenue as you progre ss towards, as opposed to
upon com pletion of, the deliverables and m ilestones that your policy suggests are
established in the contracts.  In so do ing, please tell us how the input m easures
used in that m ethod are reasonable surroga tes for the output measures established
in the contracts and how your r ecognition com plies with SAB 104.

*    *    *    *

Please respo nd to this co mment within 10 busines s days or tell us when you will
provide us with a response.  Please furnish a letter that keys your responses to our
comment and provide the request ed infor mation.  Detailed le tters greatly facilitate our
review.  Please file your letter on E DGAR under the form  type label CORRESP.

 We urge all persons who are responsible for the accuracy and adequacy of the
disclosu re in the f iling to  be cer tain that the filing include s all in form ation required under
the Securities Exchange Act of 1934 and th at they have provided all inform ation
investors require for an inform ed invest ment decision.  Since the com pany and its
manage ment are in possession of all f acts re lating to a com pany’s disclosure, they are
responsib le for the accu racy and adequacy of the disclosu res they have m ade.

 In connection with responding to our comment, please provide , in your letter, a
statem ent fr om the company ackno wledging th at:

• the com pany is respon sible for the adequacy  and accuracy of the dis closure in the
filing;
• staff comm ents or chang es to dis closure in response to staff comm ents do not
foreclose the Comm ission from  taking any actio n with respe ct to the f iling; and
• the com pany m ay not assert staff comme nts as a defense in any proceeding
initiated by the Comm ission or any person under the federal secu rities law s of the
United States.

In addition, please be advise d that the Division of Enfo rcement has access to all
inform ation you provide to the staff of the Divi sion of Corporation Fi nance in our review
of your filin g or in respo nse to our comm ent on your filing.

John L. Castello
XOMA Ltd.
March 28, 2006
Page 3

You m ay contact Jam es Peklenk, Staff Accountant, at (202) 551-3661, or Oscar
M. Young, Senior Accountant, at (202) 551- 3622 if you have questions regarding the
comment.  In this regard, do not hesi tate to contact m e, at (202) 551-3679.

Sincerely,

Jim B. Rosenberg
Senior Assistant Chief
Accountant

<DOCUMENT>
<TYPE>CORRESP
<SEQUENCE>1
<FILENAME>filename1.txt
<TEXT>

                                                                     May 4, 2005

Securities and Exchange Commission
Judiciary Plaza
450 Fifth Street, N.W.
Washington, D.C.  20549

Attention:  Michael Reedich
            Division of Corporation Finance

Re:  XOMA Ltd.
     Registration Statement on Form S-3
     File No. 333-123438
     Filed March 18, 2005, as amended April 28, 2005

Ladies and Gentlemen:

     Pursuant to Rule 461 under the Securities Act of 1933, the undersigned,
being the issuer of securities to which the referenced Registration Statement
relates, respectfully requests that the effectiveness of said Registration
Statement be accelerated so that it will become effective at 10:00 A.M. on May
6, 2005 or as soon thereafter as practicable.

     The disclosure in the filing is the responsibility of the Company. The
Company acknowledges that should the Commission or the staff, acting pursuant to
delegated authority, declare the filing effective, it does not foreclose the
Commission from taking any action with respect to the filing. The Company
further acknowledges that the action of the Commission or the staff, acting
pursuant to delegated authority, in declaring the filing effective, does not
relieve the Company from its full responsibility for the adequacy and accuracy
of the disclosures in the filing.

     The Company represents to the Commission that it will not assert this
action as a defense in any proceeding initiated by the Commission or any person
under the federal securities laws of the United States.

<PAGE>

                                       -2-

                               Very truly yours,

                               XOMA Ltd.

                               By:  /s/ Christopher J. Margolin
                                    ----------------------------------
                                    Christopher J. Margolin
                                    Vice President, General
                                    Counsel and Secretary

</TEXT>
</DOCUMENT>

<DOCUMENT>
<TYPE>CORRESP
<SEQUENCE>1
<FILENAME>filename1.txt
<TEXT>

                  (LETTERHEAD OF CAHILL GORDON & REINDEL LLP)

                                 (212) 701-3614

                                                                  April 29, 2005

     Re:  XOMA Ltd. - Registration Statement on Form S-3 filed
          March 18, 2005 (File No. 333-123438)

Dear Mr. Riedler:

     On behalf of XOMA Ltd. (the "Company"), we are responding to your letter
dated March 28, 2005 (the "Comment Letter") relating to the Company's
Registration Statement on Form S-3 (File No. 333-123438) (the "Registration
Statement"), filed with the Securities and Exchange Commission on March 18, 2005
and amended on April 28, 2005 (as amended, the "Amended Registration
Statement").

     The following sets forth the comment (the "Comment") from the Comment
Letter and the response of the Company to the Comment Letter.

Plan of Distribution section, page 58

     Comment: Please amend the disclosure in the Plan of Distribution section to
identify specifically any registered broker dealers as underwriters.

     Response: In response to the Comment, the Company has amended its
disclosure in the Amended Registration Statement to identify specifically any
registered broker dealers as underwriters. Specifically, the Company has
identified the selling securityholders that it knows to be registered broker
dealers and that such broker dealers "are" underwriters within the meaning of
Section 2(11) of the Securities Act.

<PAGE>

                                      -2-

     To aid in your review, we have sent by hand to your attention a copy of the
Amended Registration Statement marked to show the changes from the Registration
Statement. The Company believes that the response set forth above is responsive
to the Comment. Please direct any questions or further comments regarding this
filing to the undersigned at the number indicated above.

                                           Sincerely,

                                           /s/ Chris Chaice
                                           -----------------------------
                                           Chris Chaice

Jeffrey Riedler
Assistant Director
Division of Corporation Finance
Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, D.C.  20549

VIA ELECTRONIC TRANSMISSION/BY HAND

cc:   Michael Reedich
      Geoffrey E. Liebmann
      Christopher J. Margolin

</TEXT>
</DOCUMENT>

<DOCUMENT>
<TYPE>LETTER
<SEQUENCE>1
<FILENAME>filename1.txt
<TEXT>

Via Facsimile and U.S. Mail
Mail Stop 03-09

	March 28, 2005

Christopher J. Margolin, Esq.
Xoma Ltd.
2910 Seventh Street
Berkeley, CA 94710

RE: 	Xoma Ltd.
	Registration Statement on Form S-3
      Filed March 18, 2005
Registration No. 333-123438

Dear Mr. Margolin:
      This is to advise you that we have undertaken a limited
review
of the above referenced registration statement and have the
following
comment.
1. Please amend the disclosure in the Plan of Distribution section
to
identify specifically any registered broker dealers as
underwriters.

*	*	*

      As appropriate, please amend your registration statement in
response to this comment.  You may wish to provide us with marked
copies of the amendment to expedite our review.  Please furnish a
cover letter with your amendment that keys your responses to our
comment and provides any requested supplemental information.
Detailed cover letters greatly facilitate our review.  Please
understand that we may have additional comments after reviewing
your
amendment and responses to our comments.

      We urge all persons who are responsible for the accuracy and
adequacy of the disclosure in the filings reviewed by the staff to
be
certain that they have provided all information investors require
for
an informed decision.  Since the company and its management are in
possession of all facts relating to a company`s disclosure, they
are
responsible for the accuracy and adequacy of the disclosures they
have made.

      Notwithstanding our comments, in the event the company
requests
acceleration of the effective date of the pending registration
statement, it should furnish a letter, at the time of such
request,
acknowledging that:

* should the Commission or the staff, acting pursuant to delegated
authority, declare the filing effective, it does not foreclose the
Commission from taking any action with respect to the filing;

* the action of the Commission or the staff, acting pursuant to
delegated authority, in declaring the filing effective, does not
relieve the company from its full responsibility for the adequacy
and
accuracy of the disclosure in the filing; and

* the company may not assert this action as a defense in any
proceeding initiated by the Commission or any person under the
federal securities laws of the United States.

	In addition, please be advised that the Division of
Enforcement
has access to all information you provide to the staff of the
Division of Corporation Finance in connection with our review of
your
filing or in response to our comments on your filing.

	We will consider a written request for acceleration of the
effective date of the registration statement as a confirmation of
the
fact that those requesting acceleration are aware of their
respective
responsibilities under the Securities Act of 1933 and the
Securities
Exchange Act of 1934 as they relate to the proposed public
offering
of the securities specified in the above registration statement.
We
will act on the request and, pursuant to delegated authority,
grant
acceleration of the effective date.

      Please contact Michael Reedich at (202) 942-1815 or to me at
(202) 942-1840.

								Sincerely,

								Jeffrey Riedler
								Assistant Director

cc:	Geoffrey E. Liebmann, Esq.
	Cahill Gordon & Reindel LLP
	80 Pine Street
	New York, NY 10005

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1

</TEXT>
</DOCUMENT>