SecProbe.io

July 30, 2025
Shawn Matthews
Chief Executive Officer
HCM II Acquisition Corp.
100 First Stamford Place, Suite 330
Stamford, CT 06902
Simon Irish
Chief Executive Officer
Terrestrial Energy Inc.
9319 Robert D. Snyder Rd.
Charlotte, NC 28223
Re:HCM II Acquisition Corp.
Registration Statement on Form S-4
Filed on July 17, 2025
File No. 333-288735
Dear Shawn Matthews and Simon Irish:
            We have reviewed your registration statement 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 June 26, 2025 letter.
Registration Statement on Form S-4
Summary of the Proxy Statement/Prospectus
Compensation Received by the Sponsor..., page 16
We note your response to prior comment 12. Please further revise the compensation
table to additionally quantify the New Terrestrial shares issuable to Mr. Matthews (i)
pursuant to any contingent value right contained in the $4,000,000 Terrestrial
Convertible Notes and (ii) upon exercise of the 40,000 Terrestrial Warrants. Refer to 1.

July 30, 2025
Page 2
Item 1604(b)(4) of Regulation S-K. Revise as appropriate disclosure indicating the
Terrestrial Warrants will convert to New Terrestrial Common Stock, given disclosure
elsewhere indicating they will remain outstanding and become exercisable at closing.
Confirm whether the paragraph regarding $15,000 per month should appear in relation
to the Sponsor, rather than Mr. Matthews, and quantify the amount due as of the most
recent practicable date, both here and in the related person transactions section.
The Business Combination Proposal
Background of the Business Combination, page 137
2.We note your response to our prior comment 24 and reissue. Please revise to describe
negotiations relating to material terms of the transaction, including but not limited to
structure, consideration, equity financing, and continuing employment or involvement
for any persons affiliated with the SPAC before the merger. In your revised
disclosure, please explain the reasons for the terms, each party’s position on the issues
(including proposals and counter-proposals), and how you reached agreement on the
final terms.
The HCM II Board's Reasons for the Approval of the Business Combination, page 141
3.Your revisions in response to prior comment 27 do not appear to specifically address
the aspects of the unit economic criteria noted; accordingly, we reissue it. Please
include disclosure that indicates how the HCM II Board considered this
criteria. Clearly disclose if some aspects of this criteria were not met and discuss how
the Board considered these in determining the criteria was met. In this regard, we note
disclosure on page 2 that “the HCM II Board concluded that the Business
Combination met the evaluation criteria for an initial business combination disclosed
in the prospectus for the IPO.”
Summary of HCM II Financial Analysis, page 148
4.We note your responses to prior comments 28 and 29. Please further revise to clearly
disclose who prepared the Materials and when they were prepared. In this regard, we
note references to preparation by HCM II’s management, presentation by Mr.
Matthews to the Board, and estimates and projections from the management of
Terrestrial Energy or third sources ( Cf. pages 139, 148, 149). Additionally confirm
whether any financial projections with respect to Terrestrial Energy (other than the
Illustrative Unit Economics) were provided to the HCM II Board or other parties, such
as potential PIPE investors (noting that disclosure on page 149 refers to “by”); if so,
revise to include such projections. Clarify disclosure on page 137 that, "PIPE
Investors continued to only receive cleansed information" (for instance, does this refer
to nonpublic information subsequently publicly disclosed via Form 8-K, as also
referenced on page 137?).
Unaudited Prospective Unit Economics Information, page 153
We note your revisions in response to prior comment 31. Please further revise to
disclose (i) the date that the Unit Economics were prepared and, as applicable,
updated and (ii) whether or not Terrestrial Energy has affirmed to HCM II that the
Unit Economics (and any other projections) reflect the view of its management or 5.

July 30, 2025
Page 3
board as of the most recent practicable date. Refer to Item 1609 of Regulation S-K.
Additionally disclose the estimates and key assumptions referenced on page 155
(i.e., "certain estimates and other key assumptions that Terrestrial Energy's
management relied upon in preparing Terrestrial Energy's business model," including
"estimates with respect to certain expenses and working capital and an illustrative
schedule depicting a range of deployment targets of IMSR Plants"), or tell us why you
believe this is not required.
Unaudited Pro Forma Condensed Combined Financial Information, page 206
6.We note your response to prior comment 38. Please clarify whether the number of
ExchangeCo shares held by ExchangeCo shareholders are included in the number of
shares held by Terrestrial Energy Shareholders in the ownership level table on page
209.
Unaudited Pro Forma Condensed Combined Balance Sheet, page 211
7.We note that Terrestrial Energy issued Series A-1 preferred shares in July 2025.
Please revise the pro forma balance sheet to present the number of shares authorized,
issued and outstanding.
Information about Terrestrial Energy, page 249
8.We note that Terrestrial Energy's press release of June 24, 2025, announcing the
Ameresco collaboration references the "use of a natural gas-fired energy bridge in
IMSR plant operation" and "hybridization with other systems including natural gas."
Please revise your business section to discuss this hybrid energy approach and include
risk factor disclosure as appropriate.
Intellectual Property, page 268
9.We note your revisions in response to prior comment 52. Please revise disclosure that
you “currently have approximately 90 patents granted or pending,” to separately
quantify the number of granted patents and pending patents. Include the information
required by Item 101(h)(4)(vii) of Regulation S-K.
Beneficial Ownership of Securities, page 296
10.We note your response to prior comment 55. Disclosure on page 296 states, "The
expected beneficial ownership of New Terrestrial Common Shares post-Business
Combination is calculated as if Closing occurred on July 17, 2025." Accordingly,
please revise to include securities that each person has the right to acquire within 60
days of the assumed closing date, including shares underlying New Terrestrial
Warrants and Terrestrial Warrants. Note 3 on page 297 continues to refer to any
pecuniary interest that Mr. Matthews "may have;" please revise to disclose that he has
an economic interest in 2,950,000, or approximately 51.3%, of the Founder Shares
held by the Sponsor, and similarly quantify his economic interest in the shares
underlying New Terrestrial Warrants to be issued upon conversion of private
placement warrants.

July 30, 2025
Page 4
Exchangeable Shares, page F-59
11.We note your response to prior comment 60. For each type (e.g., preferred stock,
common stock) and class of issued and outstanding shares of Terrestrial Energy
Canada (Exchange) Inc. (“ExchangeCo”), provide the level of economic interest and
voting rights held by Terrestrial Energy (“parent”). If any of these shares are held by
someone other than the parent, provide the percentage of economic interests held by
them and clearly state whether they meet the definition of a noncontrolling interest in
ASC810-10-45-15 and provide your basis. If the definition is met, revise to report
these holdings as noncontrolling interests. Refer to ASC 810-10-45-16.
General
12.We note your response to prior comment 61. Please include a summary description of
the call options in an appropriate location within the proxy statement/prospectus, with
a cross-reference to more detailed discussion within notes to financial statements as
appropriate.
13.Your response to prior comment 63 indicates you are omitting the disclosure letter
pursuant to Item 601(b)(2) of Regulation S-K. Please file the company and purchaser
disclosure letters in accordance with the requirements of Item 601(b)(2)(ii), which
allows a registrant to redact specific provisions or terms of exhibits required to be
filed pursuant to Item 601(b)(2) if the registrant customarily and actually treats that
information as private or confidential and if the omitted information is not material.
Mark the exhibit index to indicate that portions of the exhibits have been omitted,
include the requisite statement on the first page of the redacted exhibits, and include
brackets indicating where the information is omitted within each exhibit.
14.We note your response to prior comment 68, and reissue it in part. You disclose that
properly tendered Public Shares will be redeemed at least one day prior to the
domestication, but also that Public Shares will not be redeemed if the business
combination is abandoned and will be returned to the holder; please reconcile and add
risk factor disclosure as applicable. Clarify the process for requesting HCM II’s
consent to withdraw tendered shares following the redemption request deadline,
referenced on pages xxiii and 106.
15.We note your revised disclosure regarding the Bridge Round Offering. Please disclose
the lock-up period of the Terrestrial Energy Convertible Notes, following which the
20 trading day period for the contingent value right begins. Additionally quantify the
shares that may be issuable pursuant to the contingent value right outside the
ownership table. Refer to Item 1604(c) of Regulation S-K. File the Terrestrial Warrant
and related documents, such as the Warrant Assignment and Assumption Agreement,
as exhibits to the registration statement.

July 30, 2025
Page 5
            Please contact Eiko Yaoita Pyles at 202-551-3587 or Hugh West at 202-551-3872 if
you have questions regarding comments on the financial statements and related
matters. Please contact Sarah Sidwell at 202-551-4733 or Jennifer Angelini at 202-551-3047
with any other questions.
Sincerely,
Division of Corporation Finance
Office of Manufacturing
cc:Kevin Manz
Eliot Robinson