SecProbe.io

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 June 26, 2025

Leigh Vosseller
Executive Vice President, Chief Financial Officer and Treasurer
TANDEM DIABETES CARE INC
12400 High Bluff Drive
San Diego, California 92130

 Re: TANDEM DIABETES CARE INC
 Form 10-K for the Year Ended December 31, 2024
 Form 8-K Filed April 30, 2025
 File No. 001-36189
Dear Leigh Vosseller:

 We have completed our review of your filings. 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.

 Sincerely,

 Division of
Corporation Finance
 Office of Industrial
Applications and
 Services
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 Document June 25, 2025 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance Office of Industrial Applications & Services 100 F Street, N.E. Washington, D.C. 20549 Attention: Nudrat Salik Jeanne Baker Re: Tandem Diabetes Care, Inc. Form 10-K for the Year Ended December 31, 2024 Form 8-K Furnished April 30, 2025 File No. 001-36189 Dear Nudrat Salik and Jeanne Baker: Tandem Diabetes Care, Inc. (the “Company”) respectfully submits its response to the comment from the staff (the “Staff”) of the Securities and Exchange Commission on the Company’s Current Report on Form 8-K contained in the Staff letter dated June 11, 2025. For convenience, the Company has set forth below the Staff’s comment followed by the Company’s response. Form 8-K Filed April 30, 2025 Exhibit 99.1, page 7 1. We note your response to comment 1. We believe the adjustment for acquired In-Process Research and Development expenses in your determination of multiple non-GAAP measures is inconsistent with Question 100.01 of the Non-GAAP Financial Measures Compliance and Disclosure Interpretation. Please confirm to us you will no longer include this adjustment in any non-GAAP financial measure presented in accordance with Item 10(e) of Regulation S-K or Regulation G. Company Response: The Company confirms that it will no longer include an adjustment for acquired in-process research and development expense in any non-GAAP financial measure presented in the future. If you have any additional questions or require any further information with respect to this response, please contact the undersigned by telephone at (858) 366-6900 or by email at lvosseller@tandemdiabetes.com. Sincerely, /s/ Leigh A. Vosseller Leigh A. Vosseller Chief Financial Officer Tandem Diabetes Care, Inc. 12400 High Bluff Drive – ››› – San Diego, CA 92130 – ››› – (858) 366-6900 – ››› – tandemdiabetes.com 1

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 June 11, 2025

Leigh Vosseller
Executive Vice President, Chief Financial Officer and Treasurer
TANDEM DIABETES CARE INC
12400 High Bluff Drive
San Diego, California 92130

 Re: TANDEM DIABETES CARE INC
 Form 10-K for the Year Ended December 31, 2024
 Form 8-K Filed April 30, 2025
 File No. 001-36189
Dear Leigh Vosseller:

 We have reviewed your May 23, 2025 response to our comment letter and
have the
following comment.

 Please respond to this letter within ten business days by providing the
requested
information or advise us as soon as possible when you will respond. If you do
not believe a
comment applies to your facts and circumstances, 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 May 13,
2025 letter.

Form 8-K Filed April 30, 2025
Exhibit 99.1, page 7

1. We note your response to comment 1. We believe the adjustment for
acquired In-
 Process Research and Development expenses in your determination of
multiple non-
 GAAP measures is inconsistent with Question 100.01 of the Non-GAAP
Financial
 Measures Compliance and Disclosure Interpretation. Please confirm to us
you will no
 longer include this adjustment in any non-GAAP financial measure
presented in
 accordance with Item 10(e) of Regulation S-K or Regulation G.
 June 11, 2025
Page 2

 Please contact Nudrat Salik at 202-551-3692 or Jeanne Baker at
202-551-3691 if you
have questions regarding comments on the financial statements and related
matters.

 Sincerely,

 Division of
Corporation Finance
 Office of Industrial
Applications and
 Services
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 Document May 23, 2025 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance Office of Industrial Applications & Services 100 F Street, N.E. Washington, D.C. 20549 Attention: Nudrat Salik Jeanne Baker Re: Tandem Diabetes Care, Inc. Form 10-K for the Year Ended December 31, 2024 Form 8-K Furnished April 30, 2025 Form 8-K Furnished February 26, 2025 File No. 001-36189 Dear Nudrat Salik and Jeanne Baker: Tandem Diabetes Care, Inc. (the “Company”) respectfully submits its responses to the comments from the staff (the “Staff”) of the Securities and Exchange Commission on the Company’s Current Report on Form 8-K contained in the Staff letter dated May 13, 2025. For convenience, the Company has set forth below the Staff’s comments followed by the Company’s responses. Form 8-K Filed April 30, 2025 Exhibit 99.1, page 7 1. We note your non-GAAP measures for the three months ended March 31, 2025 include an adjustment for acquired In-Process Research and Development (IPR&D) expenses recorded in conjunction with the revised AMF Medical share asset acquisition. Please tell us what consideration you gave to the guidance in Question 100.01 of the Non-GAAP Financial Measures Compliance and Disclosure Interpretation in determining it was appropriate to include this adjustment. Please specifically address why these expenses would not be considered normal, recurring, cash operating expenses necessary to operate your business. Company Response: The Company respectfully acknowledges the Staff’s comment and advises the Staff that it believes including adjustment for acquired In-Process Research and Development (IPR&D) expenses recorded in conjunction with the revised AMF Medical asset acquisition was appropriate after having considered the guidance referenced above. In making its decision on whether to adjust for IPR&D expense in its calculation of non-GAAP measures for the first quarter of 2025, the Company considered the following: • During the first quarter of 2023, the Company completed the acquisition of AMF Medical under the terms of a Share Purchase Agreement (the Original Transaction). The total aggregate consideration for the Original Transaction included a previous strategic investment of Swiss Francs (CHF) 8.0 million, a cash payment of CHF 62.4 million paid at the closing of the Original Transaction, and additional contingent earnout payments of up to CHF 129.6 million. The contingent earnout payments were to become payable upon the achievement of certain milestones. 12400 High Bluff Drive – ››› – San Diego, CA 92130 – ››› – (858) 366-6900 – ››› – tandemdiabetes.com 1 • In January 2025, the Company entered into a revised agreement that removed contingent liabilities previously included in the Original Transaction. Under the revised terms, the Company agreed to pay CHF 68 million, consisting of a CHF 40 million payment made in January 2025 and a final payment of CHF 28 million due in October 2025. All other payment obligations in the Original Transaction were removed. • AMF Medical was the original developer of the Sigi Patch Pump, which continued to be under development and was not yet commercially available as of March 31, 2025. The transaction was accounted for as an asset acquisition as substantially all the value of the gross assets was concentrated on a single asset. • The Company recorded acquired IPR&D expenses of $78.8 million and $75.2 million for the year ended December 31, 2023 and the three months ended March 31, 2025, respectively, representing the value of acquired in-process research and development assets with no alternative future use, and acquisition related expenses. There were no acquired IPR&D expenses in 2024. • The acquired IPR&D expense for the three months ended March 31, 2025 was not a “normal, recurring, cash operating expense” for the Company’s research and development activities, but rather was a one-time, revised milestone payment as part of an asset acquisition for a product that is under development and not commercially available. The value of the acquired in-process research and developments assets with no alternative future use was expensed as acquired IPR&D on the acquisition date. In contrast, ongoing (i.e., normal and recurring) costs to develop this asset are recorded in research and development expenses on the consolidated statements of operations, as incurred. The revised agreement entered into in January 2025 to remove the contingent liabilities from the Original Transaction was not contemplated at the time of the Original Transaction, and since the revised agreement resulted in the removal of all other payment obligations from the Original Transaction, there will be no further acquired IPR&D expense associated with the asset acquisition. • The Company presents its non-GAAP measures as an alternative view of performance. These measures reflect how management evaluates and compares the Company’s overall performance. The Company believes that disclosing these amounts is beneficial to investors and analysts, as it provides greater clarity into the Company’s financial results—specifically by distinguishing between normal, recurring research and development expenses, on the one hand, and non-recurring and unusual product acquisition expenses, on the other. Furthermore, the Company ensures transparency by clearly identifying in the press release (furnished as an exhibit to the Form 8-K) which components from the statement of operations are included in the reconciliation between GAAP and non-GAAP results, so that the presentation is not misleading. Given the circumstances, the Company believes that including the adjustment for the acquired IPR&D in its reconciliation from GAAP to non-GAAP measures for the three months ended March 31, 2025 was appropriate. 2. We are continuing to evaluate your response to comment 1 in our letter dated March 25, 2025 and may have additional comments. We acknowledge the Staff’s comment. If you have any additional questions or require any further information with respect to this response, please contact the undersigned by telephone at (858) 366-6900 or by email at lvosseller@tandemdiabetes.com. Sincerely, /s/ Leigh A. Vosseller Leigh A. Vosseller Chief Financial Officer Tandem Diabetes Care, Inc. 12400 High Bluff Drive – ››› – San Diego, CA 92130 – ››› – (858) 366-6900 – ››› – tandemdiabetes.com 2

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 May 13, 2025

Leigh Vosseller
Executive Vice President, Chief Financial Officer and Treasurer
TANDEM DIABETES CARE INC
12400 High Bluff Drive
San Diego, California 92130

 Re: TANDEM DIABETES CARE INC
 Form 10-K for the Year Ended December 31, 2024
 Form 8-K Filed April 30, 2025
 Form 8-K Filed February 26, 2025
 File No. 001-36189
Dear Leigh Vosseller:

 We have reviewed your April 4, 2025 response to our comment letter and
have the
following comments.

 Please respond to this letter within ten business days by providing the
requested
information or advise us as soon as possible when you will respond. If you do
not believe a
comment applies to your facts and circumstances, 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 March
25, 2025 letter.

Form 8-K Filed April 30, 2025
Exhibit 99.1, page 7

1. We note your non-GAAP measures for the three months ended March 31, 2025
 include an adjustment for acquired In-Process Research and Development
(IPR&D)
 expenses recorded in conjunction with the revised AMF Medical share
asset
 acquisition. Please tell us what consideration you gave to the guidance
in Question
 100.01 of the Non-GAAP Financial Measures Compliance and Disclosure
 Interpretation in determining it was appropriate to include this
adjustment. Please
 specifically address why these expenses would not be considered normal,
recurring,
 cash operating expenses necessary to operate your business.
 May 13, 2025
Page 2

Form 8-K Filed February 26, 2025
Exhibit 99.1, page 4

2. We are continuing to evaluate your response to comment 1 in our letter
dated March
 25, 2025 and may have additional comments.
 Please contact Nudrat Salik at 202-551-3692 or Jeanne Baker at
202-551-3691 if you
have questions regarding comments on the financial statements and related
matters.

 Sincerely,

 Division of
Corporation Finance
 Office of Industrial
Applications and
 Services
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 Document April 4, 2025 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance Office of Industrial Applications & Services 100 F Street, N.E. Washington, D.C. 20549 Attention: Nudrat Salik Jeanne Baker Re: Tandem Diabetes Care, Inc. Form 8-K Furnished on February 26, 2025 File No. 001-36189 Dear Ms. Salik & Ms. Baker, Tandem Diabetes Care, Inc. (the “Company”) respectfully submits its response to the comment from the staff (the “Staff”) of the Securities and Exchange Commission on the Company’s Current Report on Form 8-K contained in the Staff letter dated March 25, 2025. For convenience, the Company has set forth below the Staff’s comment followed by the Company’s response. Form 8-K Filed February 26, 2025 Exhibit 99.1 Non-GAAP Measures, page 4 1. We note that your presentation of various non-GAAP measures includes an adjustment for Tandem Choice for which you disclose that the accounting treatment for Tandem Choice had a high degree of complexity. Please tell us how you concluded that this adjustment is appropriate and does not result in tailored accounting measures. Refer to Question 100.04 of the Non-GAAP Financial Measures Compliance and Disclosure Interpretation for guidance. Company Response: The Company respectfully acknowledges the Staff’s comment and advises the Staff that it does not believe including adjustments for its Tandem Choice Program (“Tandem Choice”) in its non-GAAP sales, as well as the other non-GAAP financial measures that incorporated non-GAAP sales, represent individually tailored recognition and measurement methods that are different than those required by GAAP. The Company also notes that Tandem Choice concluded as of December 31, 2024, and consequently, Tandem Choice will not impact any non-GAAP financial measures for the year ending December 31, 2025. As disclosed in Note 2 Summary of Significant Accounting Policies on page 77 of the Company’s Annual Report on Form 10-K for the year ended December 31, 2024, in September 2022, the Company launched a technology access program referred to as Tandem Choice, that provided eligible, in-warranty t:slim X2 customers in the United States with the flexibility to obtain the newest hardware platform, Tandem Mobi, once commercially available. Participating customers had the right to purchase the alternative Tandem pump for a fee, referred to as a choice right. The Company determined that the program created a material right for which a portion of each t:slim X2 pump sales transaction price was allocated and deferred. The Company began selling Tandem Mobi insulin pumps in the first quarter of 2024 and eligibility for Tandem Choice ended in February 2024. Consequently, the Company ceased allocating and deferring a portion of the transaction price for the material right for pumps sold after that date. Eligible customers who purchased a t:slim X2 insulin pump during the program period had until December 31, 2024 to exercise their option to switch to the Tandem Mobi for a stated fee. 12400 High Bluff Drive – ››› – San Diego, CA 92130 – ››› – (858) 366-6900 – ››› – tandemdiabetes.com 1 The Company recognized the deferred sales when the obligations under Tandem Choice were satisfied. If a customer elected to participate in the program, the Company recognized upgrade fees received, and the associated cost of goods sold at the time of fulfillment. All remaining deferrals were recognized upon conclusion of the program. As the result of Tandem Choice, the Company recorded $3.5 million and $25.1 million in sales deferrals for the years ended December 31, 2022 and 2023, respectively, and when including the upgrade fees received, the Company recognized $30.2 million in net revenue for the year ended December 31, 2024. Tandem Choice had no impact on the Company’s cost of sales for the years ended December 31, 2022 and 2023. However, the Company recorded $1.3 million in cost of sales related to pump fulfillment under Tandem Choice for the year ended December 31, 2024. The Company believes that the impact of Tandem Choice on sales and other financial measures were not representative of the Company’s underlying business operations. The Company provided these non-GAAP financial measures to investors because the Company believes they were important operating performance indicators and facilitated better comparisons of its operating results across the reporting periods. While our business operations during the Tandem Choice program were similar to historical periods, the GAAP accounting treatment created the perception of a material change. For example, including the $30.2 million recognition of GAAP sales deferrals associated with Tandem Choice in 2024 resulted in a 26 percent sales increase compared to an 18 percent increase for non-GAAP sales. The Company does not believe that the above mentioned non-GAAP financial measures, or the adjustments included in the financial measures, represent “individually tailored accounting measures” as outlined in Question 100.04 of the Division of Corporation Finance’s Compliance & Disclosure Interpretations on Non-GAAP Financial Measures (the C&DIs). Question 100.04 of the C&DIs describes three examples of measures the Staff considers to be individually tailored, all of which involve the use of alternative recognition or measurement principles. However, the non-GAAP presentation excluding Tandem Choice was provided for investors to better understand our ongoing core performance, particularly when compared to prior periods. The Company therefore believes that its non-GAAP sales, as well as the other non-GAAP financial measures that incorporated non-GAAP sales, are permissible non-GAAP financial measures and do not represent individually tailored accounting measures. As noted above, Tandem Choice concluded as of December 31, 2024, and consequently Tandem Choice will not impact any non-GAAP financial measures for the year ending December 31, 2025. If you have any additional questions or require any further information with respect to this response, please contact the undersigned by telephone at (858) 366-6900 or by email at lvosseller@tandemdiabetes.com. Sincerely, /s/ Leigh A. Vosseller Leigh A. Vosseller Chief Financial Officer Tandem Diabetes Care, Inc. 12400 High Bluff Drive – ››› – San Diego, CA 92130 – ››› – (858) 366-6900 – ››› – tandemdiabetes.com 2

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 March 25, 2025

Leigh Vosseller
Executive Vice President, Chief Financial Officer and Treasurer
TANDEM DIABETES CARE INC
12400 High Bluff Drive
San Diego, California 92130

 Re: TANDEM DIABETES CARE INC
 Form 10-K for the Year Ended December 31, 2024
 Form 8-K Filed February 26, 2025
 File No. 001-36189
Dear Leigh Vosseller:

 We have reviewed your filing and have the following comment.

 Please respond to this letter within ten business days by providing the
requested
information or advise us as soon as possible when you will respond. If you do
not believe a
comment applies to your facts and circumstances, please tell us why in your
response.

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

Form 8-K Filed February 26, 2025
Exhibit 99.1
Non-GAAP Measures, page 4

1. We note that your presentation of various non-GAAP measures includes an
 adjustment for Tandem Choice for which you disclose that the accounting
treatment
 for Tandem Choice had a high degree of complexity. Please tell us how
you
 concluded that this adjustment is appropriate and does not result in
tailored
 accounting measures. Refer to Question 100.04 of the Non-GAAP Financial
Measures
 Compliance and Disclosure Interpretation for guidance.
 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.
 March 25, 2025
Page 2

 Please contact Nudrat Salik at 202-551-3692 or Jeanne Baker at
202-551-3691 if you
have questions regarding comments on the financial statements and related
matters.

 Sincerely,

 Division of
Corporation Finance
 Office of Industrial
Applications and
 Services
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December 17, 2019
Leigh Vosseller
Chief Financial Officer
Tandem Diabetes Care, Inc.
11075 Roselle Street
San Diego, CA 92121
Re:Tandem Diabetes Care, Inc.
Form 10-K for the Fiscal Year Ended December 31, 2018
Filed February 26, 2019
File No. 001-36189
Dear Ms. Vosseller:
            We have completed our review of your filings.  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.
Sincerely,
Division of Corporation Finance
Office of Life Sciences

CORRESP
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		Document

 11075 Roselle Street

San Diego, California 92121

December 6, 2019

Via EDGAR Submission

U.S. Securities and Exchange Commission

Division of Corporation Finance

100 F Street, N.E., Stop 4631

Washington, D.C. 20549

Attention:     David Burton

             Division of Corporation Finance

Office of Life Sciences

           Re:     Tandem Diabetes Care, Inc.

Form 10-K for Fiscal Year Ended December 31, 2018

Filed February 26, 2019

Form 8-K filed November 4, 2019

File No. 001-36189

Dear Mr. Burton:

This letter is being respectfully submitted by Tandem Diabetes Care, Inc., a Delaware corporation (the “Company”) in response to comments from the staff (the “Staff”) of the Securities and Exchange Commission (the “SEC”) on the Company’s above-referenced Annual Report on Form 10-K (the “Form 10-K”) and Current Report on Form 8-K (the “Form 8-K”) contained in the Staff letter dated November 7, 2019 (the “Letter”). The Company’s responses to the comments are preceded by a reproduction of the Staff’s comments as set forth in the Letter.

Form 10-K for Fiscal Year Ended December 31, 2018

Note 1 - Organization and Basis of Presentation

Revenue Recognition for Arrangements with Multiple Deliverables, page 89

1.

 We note you have identified certain complementary products as separate performance obligations that are satisfied over the four year warranty period. Please address the following:

•

 Explain in more detail the nature of the complementary products and how you evaluated these arrangements under ASC 606-10-25-19 to 25-22.

•

 Tell us the time period over which these performance obligations are recognized. In this regard we note your disclosure the performance obligations are satisfied over the four year warranty period. However we note that all of your deferred revenue is classified as a current liability on your balance sheet.

Company Response:

The Company respectfully submits that its deferred revenue balance of $4.6 million at December 31, 2018 included $3.8 million related to performance obligations which are satisfied over time. The performance obligations satisfied over time (as described more fully below) are: (1) $3.2 million related to ongoing access to diabetes management and reporting applications, also referred to as t:connect, and (2) $0.6 million related to ongoing access to the Tandem Device Updater (“TDU”).

t:connect

The Company’s t:connect diabetes management and reporting application is an online cloud-based data management application that allows continuous access for patients to upload their pump data to view historical data and trends that may be useful in the management of their therapies. The Company’s insulin pumps hold the data generated over a period of up to 90 days; once users upload their therapy management information to t:connect, the information is retained in their accounts on secure servers hosted and maintained by the Company. The t:connect application provides users, their caregivers and their healthcare providers a fast, easy and visual way to display therapy management data from their pumps and supported blood glucose meters. t:connect can also generate color-coded graphs and interactive, multi-dimensional reports that make it easy to identify therapy management trends, problems and successes.

The t:connect application is not essential to the daily use and functionality of the insulin pump. While access to this diabetes management application is provided by the Company to all pump purchasers, not all daily pump users actually utilize the t:connect application.

Tandem Device Updater

TDU is a Mac and PC-compatible tool for the remote update of the Company’s insulin pump operating software that is embedded in each of the Company's insulin pumps. The TDU enables the pump’s operating software to be updated in a manner similar to how a user would update software embedded in hardware. This proprietary online tool allows the Company to provide its in-warranty customers access to future software updates online, when made available. Such updates may include minor bug fixes or product enhancements, or they may include major upgrades that provide significant increased functionality.

While the Company considers TDU to be a feature valued by the customer, the insulin pumps have significant utility without TDU. Further, while updates and enhancements are made available by the Company through TDU to all in-warranty pump customers, not all pump users actually utilize TDU.

Distinct Goods or Services

As described above, the Company has promised to provide t:connect and TDU to each purchaser of its insulin pumps. Therefore, the Company was required to assess ASC 606-10-25-19 through 25-21 to determine whether the promises are separate performance obligations.

The Company first evaluated whether the insulin pump, t:connect and TDU are each capable of being distinct pursuant to ASC 606-10-25-19 as follows:

a.The customer can benefit from the goods or services either on their own or together.

i.

 The pump is a separate fully functional product at the date of shipment that works independently of the t:connect and TDU services. The customer can benefit from either t:connect or TDU in conjunction with the pump, which is a readily-available resource.

ii.

  In addition, the t:connect and TDU services are each considered to be distinct as the customer can benefit from each independent of the other. The t:connect gathers data for use with the customer’s health practitioner, whereas TDU allows for general software fixes and unspecified upgrades/enhancements.

b.The entity’s promise to transfer the good or services to the customer is separately identified from other promises.

i.

 At the time of the pump purchase, the Company includes the right to receive the t:connect and TDU services as identifiable services within the order confirmation process and product literature, as well as on the Company’s website. The Company is committed to providing these services over the four-year warranty period of the pump.

The Company also evaluated the customer’s ability to benefit from the goods or services pursuant to ASC 606-10-25-20 as follows:

a.For other goods or services, a customer may be able to benefit from the good or service only in conjunction with other readily-available resources. A readily-available resource is a good or service that is sold separately (by the entity or another entity) or a resource that the customer has already obtained from the entity (including goods or services that the entity will have already transferred to the customer under the contract).

i.  The pump, t:connect and TDU are provided as separate fully functional products and services when delivered. The customer can benefit from the pump as a fully functional device when it is received, whether or not the customer

chooses to utilize the functionality of t:connect or TDU, while t:connect or TDU can be used individually in conjunction with the other readily-available resources (e.g. the pump). In addition, the t:connect and TDU services are each considered to be distinct as the customer can benefit from each independent of the other.

The Company next evaluated whether the pump, t:connect, and TDU are distinct in the context of the contract pursuant to ASC 606-10-25-21 as follows:

a. The Company does not perform any services to integrate the pump, t:connect or TDU.

b. The pump, t:connect and TDU do not individually or collectively significantly modify or customize, nor are they significantly modified or customized by, one another.

c. The pump, t:connect and TDU are not highly interdependent or highly integrated as the Company is able to fulfill its contractual obligations by transferring these goods and services independently. The utility of the pump does not decrease significantly if the customer chooses not to use the t:connect or TDU services.

d. Each pump is shipped with embedded operating system software, such that the pump is fully operational upon delivery. t:connect access is provided to each pump purchaser. Upon connecting the pump to their personal computer (or Mac) and launching the t:connect application software, customers are taken through the steps to set up an account and upload their pump data.

e. Access to the TDU application is provided from the date of pump purchase throughout the four-year warranty period. Updates to pump software are provided as available. In order to complete the update, the pump purchaser needs (1) a unique update identifier which is automatically emailed to in-warranty pump customers when their pump is eligible, and (2) a compatible computer to complete the process.

Based on the facts outlined above, and pursuant to ASC 606-10-25-22, the Company concluded that the goods and services are distinct and therefore the Company allocated consideration to each of the pump, t:connect and TDU, and recognizes revenue as the good is delivered or over the period over which the services are performed.

Period Over Which These Performance Obligations are Provided and Recognized

The Company promises to provide each pump purchaser with t:connect during the period of pump usage by the customer, and with TDU during the standard four-year pump warranty period. As such, it was necessary to estimate the service period over which to recognize the value associated with each separate service. Both the t:connect and TDU services are provided and recognized over the estimated customer relationship period. The Company considers the estimated customer relationship period to be the standard four-year warranty period of the insulin pump because this best matches the expected life of the insulin pump, the insurance reimbursement approval cycle for insulin pumps (e.g. once every four years), and the estimated period of use based on the Company’s actual customer relationships.

Balance Sheet Classification

Historically, and as of December 31, 2018, the Company classified and reported all deferred revenue as a current liability. However, the value associated with providing access to t:connect and TDU beyond one year from the balance sheet date should be presented as long-term deferred revenue in accordance with the guidance in ASC 210-10-45-6. The amount that should have been reported as long-term deferred revenue as of December 31, 2018 is approximately $2.4 million, or 3.7%, of the $66.3 million of total current liabilities reported as of that date.

Based on the foregoing, the Company intends to implement a change in the balance sheet classification of deferred revenue to reflect both the current and long-term components in accordance with ASC 210-10-45-6. Considering the relative value of the long-term deferred revenue amount compared to the Company’s total and current liabilities as reflected in the balance sheet in the Form 10-K, coupled with the fact that this change has no impact on total liabilities, the Company has concluded that this error is not material to its consolidated financial statements. Accordingly, the Company will implement this change prospectively as of December 31, 2019, in connection with the filing of its Annual Report on Form 10-K for the year ending December 31, 2019.

Form 8-K filed November 4, 2019

Exhibit

2.

 We note that you discuss Adjusted EBITDA in your Third Quarter 2019 Highlights and Financial Results sections without a discussion of the most directly comparable GAAP measure. We also note that you discuss forecasted Adjusted EBITDA in your 2019 Annual Guidance section without a corresponding discussion of the most directly comparable forward-looking non-GAAP measure. Please revise future filings to present with equal or greater prominence the most directly comparable GAAP measure to Adjusted EBITDA and forecasted Adjusted EBITDA. Refer to Item 10(e)(1)(i)(A) of Regulation S-K and Question 102.10 of the Compliance & Disclosure Interpretations on the use of Non-GAAP Financial Measures.

Company Response:

The Company respectfully submits that, in disclosing Adjusted EBITDA (a non-GAAP financial measure) in the earnings press release furnished as Exhibit 99.1 to the Form 8-K (the “Earnings Release”), it specifically considered the application of Item 10(e)(1)(i) of Regulation S-K, as well as the application of the Compliance & Disclosure Interpretations on the use of Non-GAAP Financial Measures (collectively, the “Non-GAAP Disclosure Guidance”). The Company acknowledges that the Non-GAAP Disclosure Guidance requires, among other things, that whenever a non-GAAP financial measure is included in a filing with the SEC, there must be a presentation, with equal or greater prominence, of the most directly comparable GAAP financial measure. The Company respectfully confirms that, in preparing its future earnings press releases, it will follow the Non-GAAP Disclosure Guidance, including by (1) providing comparable GAAP financial measures in headings or captions that include non-GAAP financial measures, and (2) ensuring GAAP financial measures precede comparable non-GAAP financial measures.

In addition, the Company respectfully confirms that, in discussing forecasted Adjusted EBITDA in the Earnings Release without a corresponding discussion of the most directly comparable forward-looking non-GAAP financial measure, it specifically considered the application of the Non-GAAP Disclosure Guidance. In particular, the Company confirms that it was relying on the “unreasonable efforts” exception for providing non-GAAP financial measures that are forward-looking, which is set forth in Item 10(e)(1)(i)(B) of Regulation S-K. The Company submits that, because of the substantial uncertainty associated with predicting any future adjustments to its GAAP financial measures, which may include certain unique, one-time or non-recurring income or expense items that are inherently difficult to anticipate or quantify, it is not reasonably practicable to accurately predict the impact those items may have relative to the GAAP financial measures.

3.

 Additionally please revise future filings to provide a reconciliation of Adjusted EBITDA and forecasted Adjusted EBITDA to the most directly comparable financial measure calculated in accordance with GAAP. Refer to Item 10(e)(1)(i)(B) of Regulation S-K.

Company Response:

The Company respectfully confirms that, in preparing its future earnings press releases that include non-GAAP financial measures (e.g., Adjusted EBITDA), it will provide a reconciliation of the non-GAAP financial measures to the most directly comparable GAAP financial measures in a manner consistent with the Non-GAAP Disclosure Guidance.

* * * * *

In responding to the Staff’s comments in the Letter, the Company acknowledges that it is responsible for the adequacy and accuracy of the disclosures in its filings notwithstanding any review, comments, action, or absence of action by the Staff.

If you have any questions or if we can provide any additional information, please feel free to contact Ryan C. Wilkins, Esq. of Stradling Yocca Carlson & Rauth, our outside legal counsel, via telephone at (949) 725-4115 or via electronic mail at rwilkins@sycr.com, or in his absence, David Berger, Esq., Executive Vice President, Chief Legal & Compliance Officer, via telephone at (858) 255-6380 or via electronic mail at dberger@tandemdiabetes.com.

 Sincerely,

 /s/ Leigh A. Vosseller

Leigh A. Vosseller

Chief Financial Officer

Tandem Diabetes Care, Inc.

cc:     John Sheridan

Chief Executive Officer

Tandem Diabetes Care, Inc.

David Berger, Esq.

Executive Vice President, Chief Legal & Compliance Officer

Tandem Diabetes Care, Inc.

Bruce Feuchter, Esq.

Stradling Yocca Carlson Rauth, P.C.

Ryan C. Wilkins, Esq.

Stradling Yocca Carlson Rauth, P.C.

November 7, 2019
Leigh Vosseller
Chief Financial Officer
Tandem Diabetes Care, Inc.
11075 Roselle Street
San Diego, CA 92121
Re:Tandem Diabetes Care, Inc.
Form 10-K for the Fiscal Year Ended December 31, 2018
Filed February 26, 2019
Form 8-K filed November 4, 2019
File No. 001-36189
Dear Ms. Vosseller:
            We have reviewed your filing 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 these comments within ten business days by providing the requested
information or advise us as soon as possible when you will respond.  If you do not believe our
comments apply to your facts and circumstances, please tell us why in your response.
            After reviewing your response to these comments, we may have additional comments.
Form 10-K for the Fiscal Year Ended December 31, 2018
Note 1 - Organization and Basis of Presentation
Revenue Recognition for Arrangements with Multiple Deliverables, page 89
1.We note you have identified certain complementary products as separate performance
obligations that are satisfied over the four year warranty period.  Please address the
following:

•Explain in more detail the nature of the complementary products and how you
evaluated these arrangements under ASC 606-10-25-19 to 25-22.
•Tell us the time period over which these performance obligations are recognized.  In
this regard we note your disclosure the performance obligations are satisfied over the
four year warranty period.  However we note that all of your deferred revenue is
classified as a current liability on your balance sheet.

 FirstName LastNameLeigh Vosseller
 Comapany NameTandem Diabetes Care, Inc.
 November 7, 2019 Page 2
 FirstName LastName
Leigh Vosseller
Tandem Diabetes Care, Inc.
November 7, 2019
Page 2
Form 8-K filed November 4, 2019
Exhibits
2.We note that you discuss Adjusted EBITDA in your Third Quarter 2019 Highlights and
Financial Results sections without a discussion of the most directly comparable GAAP
measure.  We also note that you discuss forecasted Adjusted EBITDA in your 2019
Annual Guidance section without a corresponding discussion of the most directly
comparable forward-looking non-GAAP measure.  Please revise future filings to present
with equal or greater prominence the most directly comparable GAAP measure to
Adjusted EBITDA and forecasted Adjusted EBITDA.   Refer to Item 10(e)(1)(i)(A) of
Regulation S-K and Question 102.10 of the Compliance & Disclosure Interpretations on
the use of  Non-GAAP Financial Measures.
3.Additionally please revise future filings to provide a reconciliation of Adjusted
EBITDA and forecasted Adjusted EBITDA to the most directly comparable financial
measure calculated in accordance with GAAP.  Refer to Item 10(e)(1)(i)(B) of Regulation
S-K.
            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.
            You may contact David Burton at (202) 551-3626 or Eric Atallah, Senior Accountant, at
(202) 551-3663 if you have any questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences

CORRESP
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tndm-corresp.htm

Tandem Diabetes Care, Inc.

11075 Roselle Street

San Diego, CA 92121

May 8, 2018

SUBMITTED VIA EDGAR

Securities and Exchange Commission

Division of Corporation Finance

100 F Street, N.E.

Washington, D.C. 20549

Attention:  Tom Jones

Re:

Tandem Diabetes Care, Inc. Acceleration Request

Registration Statement on Form S-3 (File No. 333-224460)

Ladies and Gentlemen:

In accordance with Rule 461 under the Securities Act of 1933, as amended, the undersigned respectfully requests that the effective date of the above-referenced Registration Statement be accelerated so that the same will become effective at 5:00 P.M. Eastern Time on May 9, 2018.

Should the Securities and Exchange Commission have any questions regarding this acceleration request, please do not hesitate to contact Ryan C. Wilkins, an attorney with the undersigned’s outside legal counsel, Stradling Yocca Carlson & Rauth, P.C., via telephone at (949) 725-4115 or via email at rwilkins@sycr.com.

Sincerely,

TANDEM DIABETES CARE, INC.

/s/ David B. Berger

David B. Berger, Esq.

Executive Vice President, General Counsel and Secretary

cc:

Tandem Diabetes Care, Inc.

Leigh Vosseller, Senior Vice President,

Chief Financial Officer and Treasurer

Stradling Yocca Carlson & Rauth, P.C.

Bruce Feuchter, Esq.

Ryan C. Wilkins, Esq.

Mail Stop 3030
May 8, 2018

Via E -mail
Kim D. Blickenstaff
President, Chief Executive Officer  and Director
Tandem Diabetes Care, Inc.
11075 Roselle Street
San Diego, California 92121

Re: Tandem Diabetes Care, Inc.
Registration Statement on Form S-3
Filed April 26, 2018
 File No. 333 -224460

Dear M r. Blickenstaff :

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 Tom Jones at (202) 551 -3602 with any questions.

Sincerely,

 /s/ Tom Jones for

 Amanda Ravitz
Assistant Director
        Office of Electronics and Machinery

cc: David B. Berger, Esq.

CORRESP
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Acceleration Request

 OPPENHEIMER & CO. INC.

85 Broad Street, 23rd Floor

New York, NY 10004

 February 7, 2018

VIA EDGAR

 Securities and Exchange Commission

 Division of Corporation Finance

 100 F Street, N.E.

Washington, D.C. 20549

Re:    Tandem Diabetes Care, Inc.

  Registration Statement on Form S-1 (File No. 333-222553)

 Ladies and Gentlemen:

 In connection
with the above-referenced Registration Statement, and pursuant to Rule 461 under the Securities Act of 1933, as amended (the “Act”), we hereby join in the request of Tandem Diabetes Care, Inc. that the effective date of the
above-referenced Registration Statement be accelerated so that it will be declared effective at 4:00 p.m., Eastern Time, on February 8, 2018 or as soon thereafter as practicable.

The following is supplemental information supplied under Rule 418(a)(7) and Rule 460 under the Act:

(i)
Dates of distribution: January 29, 2018 through the date hereof.

(ii)
Number of prospectuses distributed: a total of approximately 250 copies were distributed to prospective underwriters, institutional investors, dealers and others.

(iii)
We have been informed by the participating underwriters that they have complied and will comply with the requirements of Rule 15c2-8 under the Securities Exchange Act of 1934.

 [SIGNATURE PAGE FOLLOWS]

 Very truly yours,

OPPENHEIMER & CO. INC.

 As Representative of the
Underwriters

 OPPENHEIMER & CO. INC.

By:

 /s/ Eric Helenek

Name: Eric Helenek

Title: Managing Director

 [Signature Page to Acceleration Request]

CORRESP
1
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CORRESP

 Tandem Diabetes Care, Inc.

11075 Roselle Street

 San
Diego, CA 92121

 February 7, 2018

SUBMITTED VIA EDGAR

 Securities and Exchange Commission

 Division of Corporation Finance

 100 F Street, N.E.
Washington, D.C. 20549

 Attention: Tom Jones

Re:
Tandem Diabetes Care, Inc.

 Registration Statement on Form S-1 (File
No. 333-222553)

 Acceleration Request

Requested Date:

February 8, 2018

Requested Time:

4:00 P.M., Eastern Time

 Ladies and Gentlemen:

Pursuant to Rule 461 of the Securities Act of 1933, as amended, Tandem Diabetes Care, Inc., a Delaware corporation (the
“Company”), hereby respectfully requests that the Securities and Exchange Commission (the “Commission”) take appropriate action to declare the above-captioned Registration Statements on Form S-1 effective at the
“Requested Date” and “Requested Time” set forth above or as soon thereafter as practicable, unless you are notified by telephone or in writing to the contrary by the Company prior to such “Requested Date” and
“Requested Time.” In the event you are so notified, you will be contacted either by Ryan C. Wilkins, an attorney with the Company’s outside legal counsel, Stradling Yocca Carlson & Rauth, P.C., or by myself.

Should the Commission have questions regarding any of the foregoing, please do not hesitate to contact Mr. Wilkins, via telephone at
(949) 725-4115 or via email at rwilkins@sycr.com, or in his absence, please contact me via telephone at (858) 255-6380 or via email at dberger@tandemdiabetes.com.

 We respectfully request that you contact Mr. Wilkins via telephone as soon as the
Registration Statement has been declared effective.

Sincerely,

TANDEM DIABETES CARE, INC.

/s/ David B. Berger

David B. Berger

General Counsel

 cc:

Tandem Diabetes Care, Inc.

Kim D. Blickenstaff, Chief Executive Officer

Leigh Voseller, Chief Financial Officer

Clifford Chance US LLP

Per B. Chilstrom, Esq.

Stradling Yocca Carlson & Rauth, P.C.

Bruce Feuchter, Esq.

 Ryan C.
Wilkins, Esq.

Mail Stop 3030
January 2 4, 2018

Via E -mail
Kim D. Blickenstaff
President and Chief Executive Officer
Tandem Diabetes Care, Inc.
11075 Roselle Street
San Diego, California 92121

Re: Tandem Diabetes Care, Inc.
Registration Statement on Form S-1
Filed January 16, 2018
 File No. 333 -222553

Dear M r. Blickenstaff :

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 Tom Jones at (202) 551 -3602 with any questions.

Sincerely,

 /s/ Tom Jones for

 Amanda Ravitz
Assistant Director
        Office of Electronics and Machinery

cc: Bruce Feuchter , Esq.

Mail Stop 3030
December 20, 2017

David B. Berger, Esq.
Executive Vice President, General Counsel
  and Secretary
Tandem Diabetes Care, Inc.
11075 Roselle Street
San Diego, California 92121

Re: Tandem Diabetes Care, Inc.
  Registration Statement on Form S-3
Filed  December 18 , 2017
  File No.  333-222143

Dear  Mr. Berger :

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 Tim Buchmiller  at (202) 551 -3635  with any questions.

Sincerely,

/s/ Tim Buchmiller  for

Amanda Ravitz
Assistant Director
Office of Electronics and Machinery

cc: Ryan C. Wilkins, Esq.
Stradling Yocca Carlson & Rauth, P.C.

CORRESP
1
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CORRESP

 Tandem Diabetes Care, Inc.

11075 Roselle Street

 San
Diego, CA 92121

 December 20, 2017

SUBMITTED VIA EDGAR

 Securities and Exchange Commission

 Division of Corporation Finance

 100 F Street, N.E.

Washington, D.C. 20549

 Attention: Tim Buchmiller, Esq.

Re:
Tandem Diabetes Care, Inc. Acceleration Request

 Registration Statement on Form S-3 (File No. 333-222143)

 Ladies and Gentlemen:

In accordance with Rule 461 under the Securities Act of 1933, as amended, the undersigned respectfully requests that the effective date of the
above-referenced Registration Statement be accelerated so that the same will become effective at 5:00 P.M. Eastern Time on December 22, 2017.

Should the Securities and Exchange Commission have any questions regarding this acceleration request, please do not hesitate to contact Ryan
C. Wilkins, an attorney with the undersigned’s outside legal counsel, Stradling Yocca Carlson & Rauth, P.C., via telephone at (949) 725-4115 or via email at rwilkins@sycr.com.

Sincerely,

TANDEM DIABETES CARE, INC.

/s/ David B. Berger

David B. Berger, Esq.

Executive Vice President, General Counsel and Secretary

 cc:

 Tandem Diabetes
Care, Inc.

 Leigh Vosseller, Senior Vice President of Finance

Stradling Yocca Carlson & Rauth, P.C.

 Bruce
Feuchter, Esq.

 Ryan C. Wilkins, Esq.

CORRESP
1
filename1.htm

CORRESP

 Tandem Diabetes Care, Inc.

11045 Roselle Street

 San
Diego, CA 92121

 March 20, 2017

SUBMITTED VIA EDGAR

 Securities and Exchange Commission

 Division of Corporation Finance

 100 F Street, N.E.
Washington, D.C. 20549

 Attention: Caleb French

Re:
Tandem Diabetes Care, Inc.

 Registration Statement on Form S-1 (File No. 333-216531)

Acceleration Request

Requested Date:
March 22, 2017

Requested Time:
4:00 P.M., Eastern Time

 Ladies and Gentlemen:

Pursuant to Rule 461 of the Securities Act of 1933, as amended, Tandem Diabetes Care, Inc., a Delaware corporation (the
“Company”), hereby respectfully requests that the Securities and Exchange Commission (the “Commission”) take appropriate action to declare the above-captioned Registration Statements on Form S-1 effective at the
“Requested Date” and “Requested Time” set forth above or as soon thereafter as practicable, unless you are notified by telephone or in writing to the contrary by the Company prior to such “Requested Date” and
“Requested Time.” In the event you are so notified, you will be contacted either by Ryan C. Wilkins, an attorney with the Company’s outside legal counsel, Stradling Yocca Carlson & Rauth, P.C., or by myself.

The Company hereby acknowledges that:

•

should the Commission or the staff of the Commission, 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.

 Should the Commission have questions regarding any of the foregoing, please do not hesitate to
contact Mr. Wilkins, via telephone at (949) 725-4115 or via email at rwilkins@sycr.com, or in his absence, please contact me via telephone at (858) 255-6380 or via email at dberger@tandemdiabetes.com.

We respectfully request that you contact Mr. Wilkins via telephone as soon as the Registration Statement has been declared effective.

Sincerely,

TANDEM DIABETES CARE, INC.

/s/ David B. Berger

David B. Berger

General Counsel

 cc:

 Tandem Diabetes
Care, Inc.

 Kim D. Blickenstaff, Chief Executive Officer

John Cajigas, Chief Financial Officer

 Clifford Chance US
LLP

 Alejandro E. Camacho, Esq.

 Per B. Chilstrom, Esq.

 Stradling Yocca Carlson & Rauth, P.C.

 Bruce
Feuchter, Esq.

 Ryan C. Wilkins, Esq.

CORRESP
1
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CORRESP

 PIPER JAFFRAY & CO.

800 Nicollet Mall

 Minneapolis,
Minnesota 55402

 March 20, 2017

 VIA EDGAR

 Securities and Exchange Commission

 Division of
Corporation Finance

 100 F Street, N.E.

 Washington, D.C.
20549

Re:
Tandem Diabetes Care, Inc.

 Registration Statement on Form S-1 (File No. 333-216531)

 Ladies and Gentlemen:

In connection with the above-referenced Registration Statement, and pursuant to Rule 461 under the Securities Act of 1933, as amended (the
“Act”), we hereby join in the request of Tandem Diabetes Care, Inc. that the effective date of the above-referenced Registration Statement be accelerated so that it will be declared effective at 4:00 p.m., Eastern Time, on March 22,
2017 or as soon thereafter as practicable.

 The following is supplemental information supplied under Rule 418(a)(7) and Rule 460 under the
Act:

(i)
Dates of distribution: March 20, 2017 through the date hereof.

(ii)
Number of prospectuses distributed: a total of approximately 250 copies were distributed to prospective underwriters, institutional investors, dealers and others.

(iii)
We have been informed by the participating underwriters that they have complied and will comply with the requirements of Rule 15c2-8 under the Securities Exchange Act of 1934.

 [SIGNATURE PAGE FOLLOWS]

 Very truly yours,

PIPER JAFFRAY & CO.

 As Representative of the Underwriters

PIPER JAFFRAY & CO.

By:

 /s/ Christie L. Christina

Name:

Christie L. Christina

Title:

 Managing Director

 Piper Jaffray &
Co.

 [Signature Page to Acceleration Request]

Mail Stop 3030
March 1 4, 2017

Via E -mail
Kim D. Blickenstaff
President and Chief Executive Officer
Tandem Diabetes Care, Inc.
11045 Roselle Street
San Diego, CA 92121

Re: Tandem Diabetes Care, Inc.
  Registration Statement on Form S-1
Filed  March 8, 2017
  File No.  333-216531

Dear Mr. Blickenstaff :

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 Caleb French  at (202) 551 -6947  with any questions.

Sincerely,

 /s/ Caleb French for

 Amanda Ravitz
Assistant Director
Office of Electronics and Machinery

cc:  Ryan C. Wilkins , Esq.
 Stradling Yocca Carlson & Rauth, P.C.

July 23, 2015

Via E -mail
Kim D. Blickenstaff
President and Chief Executive Officer
Tandem Diabetes Care, Inc.
11045 Roselle Street
San Diego, California  92121

Re: Tandem Diabetes Care, Inc.
 Form 10-K for the  fiscal  year ended December 31, 2014
 Filed February 24 , 2015
 File No. 001-36189

Dear Mr. Blickenstaff :

We have completed our review of your filings.  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 s 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 s to be certain that the filing s include  the
information the Securities Exchange Act of 1934 and all applicable  rules require.

Sincerely,

 /s/ M artin James

Martin  James
Senior Assistant Chief Accountant

CORRESP
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tndm-corresp_20150710.htm

Tandem Diabetes Care, Inc.

11045 Roselle Street

San Diego, CA 92121

July 13, 2015

SUBMITTED VIA EDGAR

Securities and Exchange Commission

Division of Corporation Finance

100 F Street, N.E.

Washington, D.C. 20549

Attention:  Martin James

Re:

Tandem Diabetes Care, Inc.

Form 10-K for the Fiscal Year Ended December 31, 2014

Filed February 24, 2015

Form 10-Q for the Quarterly Period Ended March 31, 2015

Filed April 30, 2015

File No. 001-36189

Responses to Staff comments made by letter dated July 2, 2015

Dear Mr. James:

Set forth below is the response of Tandem Diabetes Care, Inc., a Delaware corporation (the “Company”), to a comment made by the staff of the Securities and Exchange Commission (the “Staff”) by letter dated July 2, 2015 (the “Comment Letter”), relating to the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2014 (the “Form 10-K”) and Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2015 (the “Form 10-Q”).  Concurrent with the submission of this response letter, and in response to the Staff comment raised in the Comment Letter, the Company is filing separate amendments to the Form 10-K and the Form 10-Q.

The Company’s response is preceded by a reproduction of the corresponding Staff comments as set forth in the Comment Letter.

Form 10-K for the Year Ended December 31, 2014

Exhibits 31.1 and 31.2

1.

We note that the certifications filed as Exhibits 31.1 and 31.2 do not include the language regarding internal control over financial reporting in the introductory paragraph 4 as required by Item 601(b)(31) of Regulation S-K.  Also, we note that the certifications filed as Exhibits 31.1 and 31.2 to your Form 10-Q for the period ended March 31, 2015 exclude the same language, as well as paragraph 4(b) in its entirety.  Please amend your filings to include corrected certifications that provide all of the required statements.

Company Response:

In response to the Staff’s comment, the Company respectfully acknowledges that it inadvertently omitted certain statements from the certifications filed as Exhibit 31.1 and Exhibit 31.2 to each of the Form 10-K and Form 10-Q.  As requested by the Staff, the Company has filed via EDGAR, on the date hereof, an amendment to each of the Form 10-K and the Form 10-Q each of which include, as exhibits thereto, the certifications in the form required by Item 601(b)(31) of Regulation S-K.  The Company further acknowledges that the certifications, in the form filed with the amendments, were each true and correct as of the original filing date of the Form 10-K and Form 10-Q, respectively.

In responding to the Staff’s comments, the Company has authorized the undersigned to acknowledge on its behalf 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.

* * * * *

Should the Staff have additional questions or comments regarding any of the foregoing, please do not hesitate to contact the Company’s outside counsel, Ryan C. Wilkins, via telephone at (949) 725-4115 or via email at rwilkins@sycr.com, or in his absence, please contact me via telephone at (858) 255-6380 or via email at dberger@tandemdiabetes.com

Sincerely,

TANDEM DIABETES CARE, INC.

/s/ David B. Berger

David B. Berger

General Counsel

cc:

Tandem Diabetes Care, Inc.

Kim D. Blickenstaff, Chief Executive Officer

John Cajigas, Chief Financial Officer

Stradling Yocca Carlson & Rauth, P.C.

Bruce Feuchter, Esq.

Ryan C. Wilkins, Esq.

July 2 , 2015

Via E -mail
Mr. Kim D. Blickenstaff
President and Chief Executive Officer
Tandem Diabetes Care, Inc.
11045 Roselle Street
San Diego, California  92121

Re: Tandem Diabetes Care, Inc.
 Form 10-K for the  Fiscal  Year Ended December 31, 2014
 Filed February 24 , 2015
 Form 10 -Q for the Quarterly Period Ended March 31, 2015
 Filed April 30 , 2015
File No. 001-36189

Dear Mr. Blickenstaff :

We have limited our review  of your filing  to the financial statements and related
disclosures and have the following comment .  In our comment , we may ask you to provide us
with information so we may better understand your disclosure.

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

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

Form 10 -K for the Year Ended December 31, 2014

Exhibits 31.1 and 31.2

1. We note that the certifications filed as Exhibits 31.1 and 31.2 do not include the language
regarding internal control over financial reporting in the introductory paragraph 4 as
required by Item 601(b)(31) of Regulation S -K.  Also, we note that the certifications filed
as Exhibits 31.1 and 31.2 to your Form 10 -Q for the period ended March 31, 2015
exclude the same language, as  well as paragraph 4(b) in its entirety. Please amend your
filings to include corrected certifications that provide all of the required statements.

Mr. Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
July 2, 2015
Page 2

 We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the filing t o be certain that the filing includes the 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
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.

You may contact Eric Atallah  at (202) 551 -3663 or Tara Harkins , Senior Accountant , at
(202) 551 -3639 if you have questions regarding comments on the financial  statements and
related matters .  You may also contact me at (202) 551 -3671.

Sincerely,

 /s/ Martin James

Martin  James
Senior Assistant Chief Accountant

CORRESP
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CORRESP

 Tandem Diabetes Care, Inc.

11045 Roselle Street

 San
Diego, CA 92121

 November 8, 2013

SUBMITTED VIA EDGAR

 Securities and Exchange Commission

 Division of Corporation Finance

 100 F Street, N.E.

Washington, D.C. 20549

 Attention: Mary Beth Breslin, Esq.

Re:
Tandem Diabetes Care, Inc.

 Registration Statement on Form S-1 (File No. 333-
191601)

 Registration Statement on Form 8-A (File No. 001-36189)

Acceleration Request

 Requested
Date:         November 12, 2013

 Requested
Time:        4:00 P.M., Eastern Time

 Ladies and Gentlemen:

Pursuant to Rule 461 of the Securities Act of 1933, as amended, Tandem Diabetes Care, Inc., a Delaware corporation (the
“Company”), hereby respectfully requests that the Securities and Exchange Commission (the “Commission”) take appropriate action to declare the above-captioned Registration Statements on Form S-1 and Form 8-A
effective at the “Requested Date” and “Requested Time” set forth above or as soon thereafter as practicable, unless you are notified by telephone or in writing to the contrary by the Company prior to such “Requested
Date” and “Requested Time.” In the event you are so notified, you will be contacted either by Ryan C. Wilkins, an attorney with the Company’s outside legal counsel, Stradling Yocca Carlson & Rauth, P.C., or by myself.

 The Company hereby acknowledges that:

•

should the Commission or the staff of the Commission, 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.

 Should the Commission have questions regarding any of the foregoing, please do not hesitate to
contact Mr. Wilkins, via telephone at (949) 725-4115 or via email at rwilkins@sycr.com, or in his absence, please contact me via telephone at (858) 255-6380 or via email at dberger@tandemdiabetes.com.

We respectfully request that you contact Mr. Wilkins via telephone as soon as the Registration Statement has been declared effective.

Sincerely,

TANDEM DIABETES CARE, INC.

/s/ David B. Berger

David B. Berger

General Counsel

 cc:

 Tandem Diabetes
Care, Inc.

 Kim D. Blickenstaff, Chief Executive Officer

John Cajigas, Chief Financial Officer

 Clifford Chance US LLP

 Alejandro E. Camacho, Esq.

 Per B. Chilstrom, Esq.

Stradling Yocca Carlson & Rauth, P.C.

 Bruce
Feuchter, Esq.

 Timothy F. O’Brien, Esq.

 Ryan C.
Wilkins, Esq.

 MERRILL LYNCH, PIERCE, FENNER & SMITH INCORPORATED

One Bryant Park

 New York, New York
10036

 PIPER JAFFRAY & CO.

800 Nicollet Mall

 Minneapolis,
Minnesota 55402

 November 8, 2013

 VIA EDGAR

 Securities and Exchange Commission

 Division of
Corporation Finance

 100 F Street, N.E.

 Washington, D.C.
20549

Re:
Tandem Diabetes Care, Inc.

Registration Statement on Form S-1 (File No. 333-191601)

 Ladies and Gentlemen:

In connection with the above-referenced Registration Statement, and pursuant to Rule 461 under the Securities Act of 1933, as amended (the
“Act”), we hereby join in the request of Tandem Diabetes Care, Inc. that the effective date of the above-referenced Registration Statement be accelerated so that it will be declared effective at 4:00 p.m., Eastern Time, on
November 12, 2013 or as soon thereafter as practicable.

 The following is supplemental information supplied under Rule 418(a)(7) and
Rule 460 under the Act:

(i)
Dates of distribution: November 4, 2013 through the date hereof.

(ii)
Number of prospectuses distributed: a total of approximately 4,021 copies were distributed to prospective underwriters, institutional investors, dealers and others.

(iii)
We have been informed by the participating underwriters that they have complied and will comply with the requirements of Rule 15c2-8 under the Securities Exchange Act of 1934.

[SIGNATURE PAGE FOLLOWS]

Very truly yours,

MERRILL LYNCH, PIERCE, FENNER & SMITH

      INCORPORATED

PIPER JAFFRAY & CO.

As Representatives of the Underwriters

MERRILL LYNCH, PIERCE, FENNER & SMITH

      INCORPORATED

By:

 /s/ Richard A. Diaz

Name:

Richard A. Diaz

Title:

Authorized Signatory

PIPER JAFFRAY & CO.

By:

 /s/ Christie L. Christina

Name:

Managing Director

Title:

Christie L. Christina

 [Signature Page to Acceleration Request]

CORRESP
1
filename1.htm

Company Letter to the SEC for Amendment #2

 Tandem Diabetes Care, Inc.

11045 Roselle Street

 San Diego, CA 92121

 November 1, 2013

SUBMITTED VIA EDGAR

 Securities and
Exchange Commission

 Division of Corporation Finance

 100 F Street, N.E.

 Washington, D.C. 20549

Attention: Mary Beth Breslin, Esq.

Re:
Tandem Diabetes Care, Inc.

Registration Statement on Form S-1

Filed October 7, 2013

File No. 333-191601

Responses to Staff comments made by letter dated October 29, 2013

 Dear Ms. Breslin:

 Set forth below are the responses of Tandem Diabetes Care,
Inc., a Delaware corporation (the “Company”), to comments made by the staff of the Securities and Exchange Commission (the “Staff”) by letter dated October 29, 2013 (the “Comment Letter”) in
connection with the Company’s Registration Statement on Form S-1 (File No. 333-191601), which the Company initially filed on October 7, 2013 (the “Original Registration Statement”). Concurrent with the submission of
this response letter, the Company is filing Amendment No. 2 to the Original Registration Statement (as so amended, the “Registration Statement”). The Registration Statement has been updated in response to Staff comments made in
the Comment Letter. In addition, the Company has revised the Registration Statement to update other disclosures, including to reflect the effect of the Company’s anticipated reverse stock split, which the Company expects to effect prior to the
closing of the offering.

 The Company’s responses are preceded by a reproduction of the corresponding Staff comments as
set forth in the Comment Letter.

 Securities and Exchange Commission

 Tandem Diabetes Care, Inc.

 Registration Statement on Form S-1 (File No. 333-191601)

November 1, 2013

  Page
 2

 Critical Accounting Policies and Management Estimates and Assumptions

Stock Based Compensation, pages 60-65

1.
We note your October 24, 2013 response to comment 23 issued in our letter dated September 6, 2013. Please revise to disclose the reason for the significant
differences between your estimated IPO price and the estimated fair value of your stock, similar to the information provided in your response. Your disclosure should indicate how you determined the scenario probability weighting for “early
IPO,” “late IPO,” and “non-IPO” in the September 30, 2013 valuation, considering the progress with your offering. Please also discuss the significant differences in the methodologies and assumptions that were used to
estimate the IPO price with the methodologies and assumptions used in the valuation at September 30, 2013.

Company Response:

 The “Management’s Discussion and Analysis of Financial Condition and Results of Operations - Critical Accounting Policies and Management Estimates and Assumptions” section of the
Registration Statement has been revised in response to the Staff’s comment. Please see pages 65 - 67 of the Registration Statement.

Exclusive Forum, page 119

2.
We note your revised disclosure concerning forum selection. Several lawsuits are currently challenging the validity of choice of forum provisions in certificates of
incorporation. Please disclose that although you have included a choice of forum clause in your amended and restated certification of incorporation, it is possible that a court could rule that such provision is inapplicable or unenforceable.

 Company Response:

The “Description of Capital Stock” section of the Registration Statement has been revised in response to the Staff’s
comment. Please see page 124 of the Registration Statement.

 * * * * *

 Securities and Exchange Commission

 Tandem Diabetes Care, Inc.

 Registration Statement on Form S-1 (File No. 333-191601)

November 1, 2013

  Page
 3

 Should the Staff have additional questions or comments regarding any of the foregoing,
please do not hesitate to contact the Company’s outside counsel, Ryan C. Wilkins, via telephone at (949) 725-4115 or via email at rwilkins@sycr.com, or in his absence, please contact me via telephone at (858) 255-6380 or
via email at dberger@tandemdiabetes.com.

 Sincerely,

 TANDEM DIABETES CARE, INC.

/s/ David B. Berger

 David B. Berger

 General
Counsel

 cc:

Tandem Diabetes Care, Inc.

 Kim D.
Blickenstaff, Chief Executive Officer

 John Cajigas, Chief Financial Officer

 Clifford Chance US LLP

 Alejandro E. Camacho, Esq.

Per B. Chilstrom, Esq.

 Stradling Yocca
Carlson & Rauth, P.C.

 Bruce Feuchter, Esq.

 Timothy F. O’Brien, Esq.

 Ryan C. Wilkins, Esq.

October 29, 2013
Via E -mail
Kim D. Blickenstaff
President and Chief Executive Officer
Tandem Diabetes Care, Inc.
11045 Roselle Street
San Diego, CA  92121

Re: Tandem Diabetes Care, Inc.
Amendment No. 1 to Registration Statement on Form S-1
Filed  October  24, 2013
  File No. 333 -191601

Dear Mr. Blickenstaff :

We have reviewed your registration statement  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 disclo sure.

Please respond to this letter by amending your registration statement and providing the
requested information.   Where you do not believe our comments apply 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 these comments, we may have additional comments.

Critical Accounting Policies and Management Estimates and Assumptions

Stock  Based Compensation, pages 60 -65

1. We note your October 24, 2013 response to comment 23 issued in our letter dated
September 6, 2013 .  Please revise to disclose the reason for the significant differences
between your estimated IPO price and the estimated fair value of your stock, similar to
the information provided in your response.  Your disclosure should indicate how you
determined the scenario probability weighting for “early IPO ,” “late IPO ,” and “non -
IPO” in the September 30, 2013 valuation,  considering the progress with your offering.
Please also discuss the significant differences in the methodologies and assumptions that
were used to estimate the IPO price with the methodologies and assumptions used in the
valuation at September 30, 2013.

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
October 29, 2013
Page 2

 Exclusive Forum, page 119

2. We note your revised  disclosure concerning forum selection.  Several lawsuits are
currently challenging the validity of choice of forum provisions in certificates of
incorporation.  Please disclose that although you have in cluded a choice of forum clause
in your amended and restated certification of incorporation, it is possible that a court
could rule that such provision is inapplicable or unenforceable.

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 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 provide a written statement from the company
acknowledging that:

 should the Commission or the staff, acting pursuant to delegated authority, declare the
filing effective, it does not foreclose the Commissi on 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 acc uracy 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.

Please refer to Rules 460 and 461 regarding requests for acceleration.  We will consider a
written request for acceleration of the effective date of the registration statement as 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.  Please allow
adequate time for us to revie w any amendment prior to the requested effective date of the
registration statement.

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
October 29, 2013
Page 3

 You may contact Jeanne Bennett  at (202) 551-3606  or Brian Cascio, Accounting Branch
Chief,  at (202) 551-3676  if you have questions regarding comments on the financial statements
and related matters.  Please contact Joseph McCann  at (202) 551-6262 or Mary Beth Breslin ,
Senior Attorney, at (202) 551-3625  with any other questions.

Sincerely,

 /s/ Mary Beth Breslin for

 Amanda Ravitz
Assistant Director

cc (via email):  Ryan C. Wilkins , Esq.  – Stradling Yocca Carlson & Rauth, P.C.

CORRESP
1
filename1.htm

CORRESP

 Tandem Diabetes Care, Inc.

11045 Roselle Street

 San
Diego, CA 92121

 October 24, 2013

SUBMITTED VIA EDGAR

 Securities and Exchange Commission

 Division of Corporation Finance

 100 F Street, N.E.

Washington, D.C. 20549

 Attention: Mary Beth Breslin, Esq.

Re:
Tandem Diabetes Care, Inc.

Registration Statement on Form S-1

Filed October 7, 2013

File No. 333-191601

Responses to Staff comments made by letter dated October 15, 2013

 Dear Ms. Breslin:

Set forth below are the responses of Tandem Diabetes Care, Inc., a Delaware corporation (the “Company”), to comments made by
the staff of the Securities and Exchange Commission (the “Staff”) by letter dated October 15, 2013 (the “Comment Letter”) in connection with the Company’s Registration Statement on Form S-1 (File
No. 333-191601), which the Company initially filed on October 7, 2013 (the “Original Registration Statement”). Concurrent with the submission of this response letter, the Company is filing Amendment No. 1 to the
Original Registration Statement (as so amended, the “Registration Statement”). The Registration Statement has been updated in response to Staff comments made in the Comment Letter. In addition, the Company has revised the
Registration Statement to update other disclosures, including the presentation of financial results as of and for the nine months ended September 30, 2013.

The Company’s responses are preceded by a reproduction of the corresponding Staff comments as set forth in the Comment Letter. To the
extent applicable, each response contains a reference to the page number(s) where the responsive information may be found in the Registration Statement.

 Securities and Exchange Commission

Tandem Diabetes Care, Inc.

 Registration Statement on Form S-1
(File No. 333-191601)

 October 24, 2013

  Page
 2

 Artwork

1.
We refer to prior comment 1 and your revisions on the second page of graphics. We note that the text above the display monitor explains to investors that the center graphic is your “t:slim Insulin Pump.”
Accordingly, the icons and accompanying text do not appear necessary to explain your visuals. Additionally, it is not appropriate to highlight “key product features” in your artwork without balancing the presentation to highlight key
product limitations and/or competitive disadvantages. Please revise your graphics accordingly.

Company Response:

 The Company has revised the artwork on the second page to
remove the icons and accompanying text surrounding the t:slim pump.

 The Market, page 2

2.
We note your response to prior comment 10; however, the report does not clarify how the 5% estimate was calculated or whether any assumptions were necessary to derive the figure. Please provide us with this information.
To the extent assumptions were used, please revise your disclosure where you cite the figure to provide the necessary context. For instance, if the estimate does not reflect any patients who return to injections or otherwise stop using a pump,
revise to so state.

Company Response:

 When the Company submitted its responses to comments made by
the Staff in its letter dated September 6, 2013, the Company supplementally provided the Staff, pursuant to Rule 418 under the Securities Act of 1933, as amended (the “Securities Act”), a support binder (the “Support
Binder”), which provided certain backup and support information requested by the Staff. The Support Binder included a report issued by Close Concerns, Inc. (the “Close Concerns Report”), an independent consulting and
information publishing company that provides diabetes advisory services (“Close Concerns”).

 The Close Concerns Report
specifically identifies the estimated 5% annual increase estimate on page 2 thereof. The Company understands that Close Concerns derived this amount by simply dividing (x) 25,000, which represents Close Concern’s estimate of the number of
people in the U.S. who begin using insulin pump therapy each year, by (y) 500,000, which represents the high end of Close Concern’s estimated range of the aggregate number of people in the U.S. who use insulin pumps (25,000 / 500,000 =
5%). Notably, Close Concerns did not utilize the low end of the estimated range of the number of insulin pump users in the U.S. (450,000) in performing the estimated growth percentage as this would have resulted in a larger growth rate than the
5% amount provided in the Close Concerns Report.

 The Close Concerns Report does not cite, and the Company is not aware of, any additional
assumptions relied upon in calculating the estimated growth rate.

 Securities and Exchange Commission

Tandem Diabetes Care, Inc.

 Registration Statement on Form S-1
(File No. 333-191601)

 October 24, 2013

  Page
 3

 Sales and Marketing, page 76

3.
We note your revised disclosure identifying your 10% customers and refer to Schedule 7.14 to Exhibit 10.2, which indicates that you have distribution agreements with both 10% customers. Please file these agreements as
material contracts or explain why you believe they are not material.

Company Response:

 The Company respectfully submits that it should not be
required to file any of its distribution agreements as material contracts as none of the agreements individually is material to the Company’s business. As disclosed in the “Business – Sales and Marketing” section of the
Registration Statement, as of September 30, 2013, the Company had entered into separate agreements with approximately 27 independent distributors. These agreements are all non-exclusive arrangements, and have one-year terms with automatic
one-year renewal terms. In each case, either party may opt out of any automatic renewal by providing prior notice. The Company also expects to enter into additional agreements with other independent distributors in the near-term. Given the volume of
independent distributor agreements that it has entered into, the regularity with which it pursues further opportunities to enter into similar agreements, as well as the short-term, non-exclusive nature of the business arrangements, the Company
believes the independent distributor agreements are entered into, and will continue to be entered into, in the ordinary course of its business. As a result, the Company respectfully submits that the agreements should be exempt from the exhibit
filing requirements pursuant to Item 601(b)(10)(i) of Regulation S-K.

 In addition, although the Company has disclosed that certain
independent distributors have historically accounted for greater than 10% of the Company’s sales, the percentage of Company sales that are derived from individual distributor relationships has already decreased since the commercialization of
t:slim in August 2012. For example, RGH Enterprises, Inc. (“RGH”) accounted for 19.3% of the Company’s sales for the period ended December 31, 2012, but more recently accounted for only 17.2% of the Company’s sales
for the nine month period ended September 30, 2013, as disclosed in the Registration Statement. Similarly, Solara Medical Supplies, Inc. (“Solara”) accounted for 15.7% of the Company’s sales for the period ended
December 31, 2012, but more recently accounted for less than 10% of the Company’s sales for the nine month period ended September 30, 2013. For the nine month period ended September 30, 2013, another independent distributor, CCS
Medical, Inc. (“CCS”), accounted for 11.7% of the Company’s sales. The Company also believes it is important to note that, in addition to the sales generated through RGH and CCS, for the nine month period ended
September 30, 2013, there were five other significant customers that each accounted for between 5% and 10% of the Company’s total sales, which further demonstrates the broad distribution of the Company’s sales through multiple
channels.

 The decreases in the percentages of Company sales made to particular distributors, such as RGH and Solara, are attributable to
both the large and growing number of independent

 Securities and Exchange Commission

Tandem Diabetes Care, Inc.

 Registration Statement on Form S-1
(File No. 333-191601)

 October 24, 2013

  Page
 4

distributors with which the Company has entered into distribution agreements (which necessarily divide total Company sales made to distributors by a larger number of distributors) as well as the
Company’s increased focus on generating sales directly through its sales, clinical and marketing team (which has the effect of reducing the percentage of sales to independent distributors as a function of total Company sales, further reducing
the percentage of Company sales to any particular distributor). As a result of these and other factors, the Company believes that the percentage of its total sales that are made to independent distributors will continue to decrease over time.
Accordingly, the Company does not believe that its business is or will be substantially dependent on any single independent distributor agreement for purposes of Item 601(b)(10)(ii)(B) of Regulation S-K. In addition, the Company believes that
none of the individual agreements are otherwise material to an investor’s understanding of the Company’s business.

 The Company
also notes that it anticipates that the percentage of its total sales made to any individual independent distributor will vary year-to-year, and even from quarter-to-quarter, as illustrated by the decreases described above for RGH and Solara and the
increase for CCS. For this reason, as well as the broad distribution of sales among various independent distributors as described above, the Company believes that placing undue focus on any particular distributor or group of distributors would be
inappropriate and potentially even misleading to investors.

 Finally, although the distribution agreements were identified on Schedule 7.14
to Exhibit 10.2, the Company respectfully notes to the Staff that the Company’s representations and warranties contained in Exhibit 10.2 were not intended to be treated as categorical statements of fact, but rather as a way of allocating the
risk to one of the parties if those statements prove to be inaccurate. In disclosing those agreements on Schedule 7.14 to Exhibit 10.2, the Company applied contract standards of “materiality” that are different from the concept of
“materiality” under applicable securities laws.

 Notwithstanding the foregoing, in response to the Staff’s comment, the
Company has supplemented its disclosure in the “Business – Sales and Marketing” section of the Registration Statement to inform investors of the non-exclusive nature of the independent distributor agreements as well as the annual
termination rights generally available to both the Company and the independent distributor pursuant to those agreements.

 Manufacturing and Quality
Assurance, page 79

4.
With a view to disclosure concerning your manufacturing, please tell us about the nature of the OEM Agreement and the Manufacturing Agreement which are referenced in items 6 and 33 in Schedule 7.14 to Exhibit 10.2.

Company Response:

 The Company believes that each of the OEM Agreement and the
Manufacturing Agreement referenced in the Staff’s comment were entered into in the ordinary course of the Company’s business. Furthermore, the Company does not believe that its business is or will be substantially dependent on either the
OEM Agreement or the Manufacturing Agreement.

 Securities and Exchange Commission

Tandem Diabetes Care, Inc.

 Registration Statement on Form S-1
(File No. 333-191601)

 October 24, 2013

  Page
 5

 The OEM Agreement
relates to the Company’s purchase of infusion sets that are sold to customers separate from the t:slim pump. The infusion sets that are the subject of the OEM Agreement are only one of several brands sold by the Company. As disclosed in the
“Management’s Discussion and Analysis of Financial Condition and Results of Operations” section of the Registration Statement, the Company’s sales of all pump-related supplies and accessories in the aggregate, including infusion
sets, cartridges, belt clips and other accessories, comprised only approximately 9.0% of the Company’s sales for the nine month period ended September 30, 2013, of which sales of infusion sets that we supplied under the OEM Agreement
comprised only a small portion. Due to both the relatively small amount of sales generated from infusion sets that the Company purchases under the OEM Agreement, and the fact that the Company also sells several other brands of infusion sets under
different contractual arrangements, the Company’s business is not substantially dependent on the OEM Agreement or the products that are the subject of the agreement for purposes of Item 601(b)(10)(ii)(B) of Regulation S-K. In addition, the
Company believes that the agreement is not otherwise material to an investor’s understanding of the Company’s business.

 The
Manufacturing Agreement relates to the manufacture and testing of a component of the t:slim pump. However, the agreement does not contain any purchase obligations or commitments by the Company. Purchase commitments are subject to separate purchase
orders, and only to the extent that the Company actually places any orders will the terms of the agreement apply. In addition, the agreement is subject to termination by the Company upon short notice and without penalty. The Company believes that it
could identify alternative suppliers within the notice period if necessary. Due to the lack of minimum purchase commitments and the fact that the Company believes it can readily identify replacement suppliers, the Company’s business is not
substantially dependent on the agreement or the components that are the subject of the agreement for purposes of Item 601(b)(10)(ii)(B) of Regulation S-K. In addition, the Company believes that the agreement is not otherwise material to an
investor’s understanding of the Company’s business.

 Finally, the Company respectfully submits that, although the OEM Agreement
and the Manufacturing Agreement were identified on Schedule 7.14 to Exhibit 10.2, the considerations discussed in the Company’s response to Staff comment 3 in relation to the representations and warranties contained in Exhibit 10.2 apply
equally in this context.

 For the foregoing reasons, the Company respectfully submits that it should not be required to revise the
Registration Statement in response to the Staff comment.

 Intellectual Property, page 81

5.
We note your response to prior comment 33. Given the size of the license fee payment relative to your revenues and your operating and net losses, it is not clear how you determined that the agreement is not required to
be disclosed and filed as an exhibit to your registration statement. Please revise to disclose the identity of the unnamed party and file the agreement.

 Securities and Exchange Commission

Tandem Diabetes Care, Inc.

 Registration Statement on Form S-1
(File No. 333-191601)

 October 24, 2013

  Page
 6

Company Response:

 The third paragraph of the “Business – Intellectual
Property” section and the second paragraph of the “Management’s Discussion and Analysis of Financial Condition and Results of Operations – Capitalized Intellectual Property” section have been revised to provide the identity
of the party to the agreement. The redacted version of the agreement has also been filed as Exhibit 10.20 to the Registration Statement. The Company is seeking to omit confidential portions of the agreement pursuant to Rule 406 promulgated under the
Securities Act.

 Market Comparisons, page 99

6.
We note your response to prior comment 36; however, to the extent that you benchmark total compensation to that of the companies contained in the surveys you or your consultants used, please revise your disclosure to
identify the surveys used and their components, including component companies. Refer to Item 402(b)(2)(xiv) of Regulation S-K.

Company Response:

 The C

CORRESP
1
filename1.htm

Lawyer's SEC Letter

  STRADLING YOCCA CARLSON & RAUTH, P.C.

  660 NEWPORT CENTER DRIVE, SUITE 1600

  NEWPORT BEACH, CA 92660-6422

  SYCR.COM

             NEWPORT BEACH

            RENO

            SAN DIEGO

            SACRAMENTO

            SAN FRANCISCO

            SANTA BARBARA

            SANTA MONICA

 October 24, 2013

VIA EDGAR AND FEDEX

 FOIA CONFIDENTIAL TREATMENT REQUESTED

BY TANDEM DIABETES CARE, INC.

 United States Securities and Exchange Commission

Division of Corporation Finance

 100 F Street, N.E.

Washington, D.C. 20549

 Attention: Mary Beth Breslin, Esq.

Re:
Tandem Diabetes Care, Inc.

 Registration Statement on Form S-1

Filed October 7, 2013

File No. 333-191601

 Dear
Ms. Breslin:

 On behalf of our client, Tandem Diabetes Care, Inc., a Delaware corporation (the “Company”), we are
submitting this letter in response to comments received from the staff (the “Staff”) of the Securities and Exchange Commission (the “Commission”) by letter dated September 6, 2013 (the “Comment
Letter”), relating to the Company’s draft registration statement on Form S-1 confidentially submitted to the Commission on August 12, 2013, which was subsequently amended in response to the Comment Letter and confidentially
submitted to the Commission on September 30, 2013 (as so amended, the “Confidential Registration Statement”). The Confidential Registration Statement was filed publicly on October 7, 2013 (File No. 333-191601) (the
“Original Registration Statement”). Concurrent with the submission of this response letter, the Company is filing Amendment No. 1 to the Original Registration Statement (as so amended, the “Registration
Statement”). In this letter, we are only responding to comment number 23 in the Comment Letter, which has been reproduced in its entirety below.

Confidential Treatment Request

 Due to
the commercially sensitive nature of information contained herein, the Company hereby requests, pursuant to 17 C.F.R. § 200.83, that certain portions of this letter be maintained in confidence, not be made part of any public record and not be
disclosed to any person, as they contain confidential information. The Company has excluded the confidential portions of this letter from the copy of the letter filed on EDGAR.

 1

 FOIA Confidential Treatment Requested

By Tandem Diabetes Care, Inc.

 Registration Statement
on Form S-1

 Filed October 7, 2013

 File No.
333-191601

 In accordance with 17 C.F.R. § 200.83(d)(1), if any person (including any
governmental employee who is not an employee of the Commission) should request access to or an opportunity to inspect this letter, we request that we be immediately notified of any such request, be furnished with a copy of all written materials
pertaining to such request (including, but not limited to, the request itself) and be given at least ten business days advance notice of any intended release so that the Company may, if deemed necessary or appropriate, pursue any remedies available
to it. In such an event, we respectfully request that you telephone the undersigned rather than rely upon the U.S. mail for such notice. The address and telephone number for the undersigned is c/o Stradling Yocca Carlson & Rauth, P.C., 660
Newport Center Drive, Suite 1600, Newport Beach, CA 92660, Attention: Ryan C. Wilkins, Esq., telephone number (949) 725-4115.

 Staff Comment and
Company Response

 Critical Accounting Policies and Management Estimates and Assumptions

Stock Based Compensation, pages 57-61

23.
After pricing information is available, please revise to provide a specific discussion of each significant factor contributing to significant differences between the estimated fair value of your stock and the estimated
IPO price (or pricing range) for the 12 months prior to the IPO. Please note that we are deferring final evaluation of share-based compensation until the estimated offering price is specified, and we may have further comments in that regard when you
file an amendment containing that information.

 Company Response: We respectfully advise the Staff that on
October 22, 2013, the Company, based on information provided by its underwriters, determined that the estimated offering prices to be included on the cover of the Company’s preliminary prospectus (the “Cover Page”) is
likely to be in the range of $[***] to $[***] per share. The midpoint of the estimated price range is $[***] per share. The Company anticipates making a final determination of the estimated offering prices to be included on the Cover Page within the
next 7 to 10 days.

 In comparison, the Company’s board of directors, with input from management, determined the fair value of the
Company’s common stock to be $4.78 per share as of September 30, 2013. This amount was determined after considering the objective and subjective factors described in the “Management’s Discussion and Analysis of Financial
Condition and Results of Operations” section of the Registration Statement, which included, but was not limited to, consideration of material Company operational and development milestones and a valuation report prepared by an independent
third-party valuation specialist.

 Please note that the foregoing per share amounts, and the other per share amounts set forth in this
letter, do not reflect the impact of an anticipated reverse stock split, which the Company plans to effect immediately prior to the closing of the initial public offering.

CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
DOCUMENT, MARKED BY [***], HAS BEEN OMITTED AND FILED SEPARATELY WITH THE
COMMISSION PURSUANT TO 17 C.F.R. §200.83

 2

 FOIA Confidential Treatment Requested

By Tandem Diabetes Care, Inc.

 Registration Statement
on Form S-1

 Filed October 7, 2013

 File No.
333-191601

 As is typical in initial public offerings, the final estimated price range included on the
Cover Page will not be derived using a formal determination of fair value, but instead will be determined primarily through negotiation between the Company and its underwriters. Among the factors that the Company expects to consider in setting the
estimated price range for the offering are the following:

•

an analysis of the typical valuation ranges seen in recent initial public offerings by companies in the Company’s industry, and by companies conducting initial public offerings generally;

•

the recent market prices of, and the demand for, publicly-traded common stock of companies in the Company’s industry, and public companies generally;

•

the general condition of the securities markets;

•

an assumption that there would be a receptive public trading market for medical device companies such as the Company;

•

an assumption that there would be sufficient demand for the Company’s common stock to support an offering of the size contemplated by the Registration Statement; and

•

preliminary discussions with the underwriters concerning the potential valuation of the Company.

The midpoint of the estimated price range for the offering of $[***] per share (the “Midpoint Price”), exceeds the fair
value of the Company’s common stock of $4.78 per share as of September 30, 2013, which was determined as described above (the “Prior Valuation Price”) by $[***] per share. The Company respectfully submits that the
difference between the Prior Valuation Price and the Midpoint Price is primarily attributable to the fact that the methodology for determining the two prices is different in important ways.

The Prior Valuation Price resulted from the consideration of multiple liquidity scenarios (the “early IPO”, “late IPO” and
“non-IPO” (or “stay private”) scenarios), not all of which allocate value to the Company’s stockholders on a fully-diluted, as-converted to common stock basis. In contrast, the Midpoint Price assumes with 100% probability
that the Company will complete the contemplated initial public offering (in connection with which all of the Company’s outstanding preferred stock will be converted into common stock) during the fourth quarter of 2013, as well as certain other
factors.

 In particular, in calculating the Prior Valuation Price, the consideration of multiple liquidity scenarios with different
probability weightings, along with the application of a present value discount factor of 24% and a discount for lack of marketability (“DLOM”) (10%, 14% and 25% in the “early IPO”, “late IPO” and
“non-IPO” (or “stay private”) scenarios, respectively)

CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
DOCUMENT, MARKED BY [***], HAS BEEN OMITTED AND FILED SEPARATELY WITH THE
COMMISSION PURSUANT TO 17 C.F.R. §200.83

 3

 FOIA Confidential Treatment Requested

By Tandem Diabetes Care, Inc.

 Registration Statement
on Form S-1

 Filed October 7, 2013

 File No.
333-191601

accounted for approximately $[***] of the $[***] per share difference between the Prior Valuation Price and the Midpoint Price. The following points illustrate this calculation in greater detail:

•

The September 30, 2013 valuation report prepared by the Company’s valuation specialist contained three liquidity scenarios. The “non-IPO” (or “stay private”) scenario (which, among other
things, facilitated the inclusion of various potential liquidity outcomes in which the Company’s preferred stockholders would retain their rights and preferences upon a liquidation of the Company) resulted in a fair value determination of $2.82
per share prior to applying the DLOM of 25%. The “early-IPO” scenario results in a higher fair value per share determination than the “non-IPO” scenario because, under the “early IPO scenario, the Company’s preferred
stock would convert into common stock in connection with the offering and, therefore, the liquidation preferences associated with the preferred stock would be eliminated upon completion of the offering. Accordingly, after applying the indicated DLOM
and a scenario probability weighting of 30%, the consideration of the “non-IPO” scenario accounted for approximately $[***] per share of the $[***] per share difference between the Prior Valuation Price and the Midpoint Price;

•

In determining the fair value of the Company’s common stock, the September 30, 2013 valuation report utilized a DLOM equal to 10%, 14% and 25% in the “early IPO”, “late IPO” and
“non-IPO” scenarios, respectively. The application of these factors accounted for approximately $[***] per share of the $[***] per share difference between the Prior Valuation Price and the Midpoint Price; and

•

The Guideline Company Method was applied to the “early IPO” and “late IPO” scenarios. A present value discount factor of 24% was applied to each scenario, resulting in a determination of the fair
value of the Company’s common stock of $6.06 per share and $8.89 per share prior to applying a DLOM equal to 10% and 14% for the “early IPO” and “late IPO” scenarios, respectively. Accordingly, after applying the indicated
DLOM and the scenario probability weighting (55% for the “early IPO” scenario and 15% for the “late IPO” scenario, respectively), the consideration of a present value discount factor accounted for approximately $[***] per share
of the $[***] per share difference between the Prior Valuation Price and the Midpoint Price.

 The Company believes that the
remaining difference between the Prior Valuation Price and the Midpoint Price is justified by (i) the fact that the valuation report prepared by the Company’s third-party valuation specialist utilized a quantitative methodology to
determine the fair value of the Company’s common stock, which may differ from the more qualitative and subjective methodology that may be used by some public market investors to determine the price they are willing to pay in the offering, and
(ii) other factors, such as the inherent uncertainty of completing a successful initial public offering and the possibility that the actual offering price could be substantially lower than the estimated offering price range provided by the
Company’s underwriters.

CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
DOCUMENT, MARKED BY [***], HAS BEEN OMITTED AND FILED SEPARATELY WITH THE
COMMISSION PURSUANT TO 17 C.F.R. §200.83

 4

 FOIA Confidential Treatment Requested

By Tandem Diabetes Care, Inc.

 Registration Statement
on Form S-1

 Filed October 7, 2013

 File No.
333-191601

 In conclusion, the Company respectfully submits that the difference between the latest
valuation (i.e., the Prior Valuation Price) and the estimated IPO price (i.e., the Midpoint Price) is reasonable in light of the considerations outlined above.

The Company expects to add disclosure to the effect of the foregoing in its next amendment to the Registration Statement, which the Company
expects will include the price range. The Company anticipates filing this amendment in the next 7 to 10 days.

 In addition, as requested by
the Staff, the Company confirms that it will continue to update the disclosures in its Registration Statement to reflect all equity-related transactions, including the issuance of any options, warrants, convertible notes or shares of preferred
stock, through the effective date of the Registration Statement.

 * * * * *

CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
DOCUMENT, MARKED BY [***], HAS BEEN OMITTED AND FILED SEPARATELY WITH THE
COMMISSION PURSUANT TO 17 C.F.R. §200.83

 5

 FOIA Confidential Treatment Requested

By Tandem Diabetes Care, Inc.

 Registration Statement
on Form S-1

 Filed October 7, 2013

 File No.
333-191601

 Should the Staff have any questions or comments regarding any of the foregoing, please do not
hesitate to contact the undersigned via telephone at (949) 725-4115 or via email at rwilkins@sycr.com, or in his absence, Bruce Feuchter via telephone at (949) 725-4123 or via email at feuchter@sycr.com.

Sincerely,

STRADLING YOCCA CARLSON & RAUTH, P.C.

/s/ Ryan C. Wilkins

Ryan C. Wilkins

 cc:

 Tandem Diabetes
Care, Inc.

 Kim D. Blickenstaff, Chief Executive Officer

John Cajigas, Chief Financial Officer

 David B. Berger, Esq.,
General Counsel

 Clifford Chance US LLP

 Alejandro E.
Camacho, Esq.

 Per B. Chilstrom, Esq.

 Stradling Yocca
Carlson & Rauth, P.C.

 Bruce Feuchter, Esq.

Timothy F. O’Brien, Esq.

 6

October 15 , 2013
Via E -mail
Kim D. Blickenstaff
President and Chief Executive Officer
Tandem Diabetes Care, Inc.
11045 Roselle Street
San Diego, CA  92121

Re: Tandem Diabetes Care, Inc.
Registration Statement on Form S-1
Filed  October  7, 2013
  File No. 333 -191601

Dear Mr. Blickenstaff :

We have reviewed your registration statement  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 by amending your registration statement and providing the
requested information.   Where you do not believe our comments apply 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 these comments, we may have additional comments.

Artwork

1. We refer to prior comment 1 and your revisions on the second page of graphics.  We note
that the text above the display monitor explains to investors that the center graphic is
your “t:slim Insulin Pump.”  Accordingly, the icons and accompanying text do not appear
necessary to explain your visuals.  Additionally, it is not appropriate to  highlight “key
product features” in your artwork without balancing the presentation to highlight key
product limitations and/or competitive disadvantages.   Please revise your graphics
accordingly.

The Market, page 2

2. We note your response to prior comment 10; however, the report does not clarify how the
5% estimate was calculated or whether any assumptions were necessary to derive the
figure.  Please provide us with this information .  To the extent assumptions were used,
please revise your disclosur e where you cite the figure to provide the necessary context.

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
October 15 , 2013
Page 2

 For instance, if the estimate does not reflect any patients who return to injections or
otherwise stop using a pump, revise to so state.

Sales and Marketing, page 76

3. We note your revised di sclosure identifying your 10% customers and refer to Schedule
7.14 to Exhibit 10.2, which indicates that you have distribution agreements with both
10% customers.  Please file these agreements as material contracts or explain why you
believe they are not m aterial.

Manufacturing and Quality Assurance, page 79

4. With a view to disclosure concerning your manufacturing, please tell us about the nature
of the OEM Agreement and the Manufacturing Agreement which are referenced in items
6 and 33 in Schedule 7.14 to  Exhibit 10.2.

Intellectual Property, page 81

5. We note your response to prior comment 33 .  Given the size of the license fee payment
relative to your revenues and  your operating and net losses , it is not clear how you
determined that the agreement is not required to be disclosed and filed as an exhibit t o
your registration statement.  Please revise to disclose the identity of the unnamed party
and file the agreement.

Market Comparisons, page 99

6. We note your response to prior comment 36; however, to the extent that you benchmark
total compensation to that of the companies contained in the surveys you or your
consultants used, please revise your disclosure to identify the surveys used and their
components,  including component companies.  Refer to Item 402( b)(2)(xiv) of
Regulation S -K.

We urge al l 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 Act of 1933 and
all applicable Securities Act rules require.   Since the company and its manage ment 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 provide a written statement from the company
acknowledging that:

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

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
October 15 , 2013
Page 3

 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 t he 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.

Please refer to Rules 460 and 461 regarding requests for acceleration.  We will consider a
written request for acceleration of the effective date of the registration statement as confirmation
of the fact that those requesting acceleration are aware of thei r 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.  Please allow
adequate time for us to rev iew any amendment prior to the requested effective date of the
registration statement.

You may contact Jeanne Bennett  at (202) 551-3606  or Brian Cascio, Accounting Branch
Chief,  at (202) 551-3676  if you have questions regarding comments on the financial statements
and related matters.  Please contact Joseph McCann  at (202) 551-6262 or Mary Beth Breslin ,
Senior Attorney, at (202) 551-3625  with any other questions.

Sincerely,

 /s/ Mary Beth Bresl in for

 Amanda Ravitz
Assistant Director

cc (via email):  Ryan C. Wilkins , Esq.  – Stradling Yocca Carlson & Rauth, P.C.

September 6, 2013

Via E -mail
Kim D. Blickenstaff
President and Chief Executive Officer
Tandem Diabetes Care, Inc.
11045 Roselle Street
San Diego, CA  92121

Re: Tandem Diabetes Care, Inc.
Draft Registration Statement on Form S-1
Submitted August 12, 2013
  CIK No. 1438133

Dear Mr. Blickenstaff :

We have reviewed your draft registration statement  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 by providing the requested information and either submitting
an amended draft registration statement or  publicly  filing your registration statement on
EDGAR.  If you do not believe our comments apply to your facts and circumst ances or do not
believe an amendment is appropriate, please tell us why in your response.

After reviewing the information you provide in response to these  comments  and your
amended draft registration statement or filed registration statement,  we may have additional
comments.

Artwork

1. Please note that you may include text in your artwork only to the extent necessary to
explain briefly the visuals in the presentation.  Text such as “touch simplicity,”
“advanced technology,” and “ manufacturing excellence” does not appear necessary to
explain the visuals .  Additionally, it is unclear why the visuals and accompanying text in
the right column on the third page of your graphics is necessary.  Please revise
accordingly.

2. We note that the third page of the front graphics and on the back prospectus cover page
include products that you do not design, develop or sell or that are currently in
development.  Given the prominence of the artwork, it is inappropriate to include
products that you do not sell or  that are in development, have not been approved by

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
September 6, 2013
Page 2

 regulatory agencies, and may never generate revenue in such a prominent manner. Please
revise.

Market and Industry Data and Forecasts, page ii

3. We note your statement that forecasts are “particularly li kely to be inaccurate.”  It is
unclear why you believe it is appropriate to include such information in a registration
statement.  Please remove this language disclaiming responsibility for your disclosure
and remove any forecast that is likely to be inacc urate.

Prospectus Summary, page 1

4. Please revise the italicized introductory paragraph to clarify that the Summary discusses
all material aspects of the offering.  Refer to Item 503(a) of Regulation S -K.

Overview, page 1

5. We note your disclosure highlig hting sales  in the year ended December 31, 2012 and six -
month period ended June 30, 2013 .  Please balance your disclosure by highlighting your
net losses in these periods.   Also disclose the accumulated deficit as of June 30, 2013.

6. In the first paragrap h, please revise to clarify what you mean by “Micro -Delivery
Technology .” In the fourth paragraph, please briefly explain the significance of your
pump being one of the first cleared under the FDA’s Infusion Pump Improvement
Initiative.  Finally, in the fi fth paragraph, please revise to disclose the basis for your
belief that you have an opportunity to “rapidly” increase sales.

7. We note your statement in the third paragraph here and in the third paragraph on page 2
regarding the size of the target market.  Please revise to identify the source of this data.

8. Please provide us support for your statement in the fifth paragraph that a significant
number of customers have converted from multiple daily injection to t:sli m for their
insulin therapy, and tell us, with a view toward disclosure, what percentage of your
customers converted.

The Market, page 2

9. We note the inclusion of third -party data in the prospectus, such as the market data from
The International Diabet es Federation, the National Diabetes Information Clearinghouse,
JDRF and others.  Please provide us with copies of the sources of this data, clearly
marking the relevant sections of the reports that support the data you have included in the
prospectus and the page number of your prospectus where such data has been used. Also
tell us whether the data was commissioned for use in connection with the registration
statement.

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
September 6, 2013
Page 3

 10. Please tell us how you calculated the 7% “annual increase in pump use” as disclosed on
page 2, including any assumptions used.  Also tell us whether the rate calculated takes
into account patients who return to insulin injections or otherwise stop using the pump.

Our Solution, page 3

11. We note your disclosure here and elsewhere concerning use of the “science of human
factors” to guide your product development process.  Please revise to explain how your
approach is “fundamentally different from the traditional medical device development
process.”

12. Please provide us objective, independent support for your statements here  and in  your
Business section regarding the superior or unique design and performance of your insulin
pump.  By means of nonexclusive example, we note  your statement s that t:slim is the
“slimmest and smallest durable  insulin pump on the market ” and that it is “capable of
delivering the smallest increment of insulin to users of any pump currently available.”

Implications of being an Emerging Growth Company, page 5

13. Please  supplementally provide us with copies of all written communications, as defined
in Rule 405 under the Securities Act, that you , or anyone authorized to do so on your
behalf , present to potential investors in reliance on Section 5(d) of the Securities Act,
whether or not they retain copies of the communications.   Similarly, please
supplementally provide us with any research reports about you that are published or
distributed in reliance upon Section 2(a)(3) of the Securities Act of 1933 added by
Section 105 (a) of the Jumpstart Our Business Startups Act by any broker or dealer that is
participating or will participate in your offering.

Risk Factors, page 10

14. We note your risk factor beginning on page 10 combining the risks relating to reliance on
a sole product and the risks relating to market acceptance of your product.  Please revise
to provide separate risk factor disclosure for each of these distinct risks .  Please also add
risk factor disclosure that discusses the risks relating to market adoption of your insulin
pump  as compared to traditional injection therapy , separate from a discussion of risks
relating to adoption of your pump technology compared with established pump
technology.  Also a dd appropriate risk factor disclosure of the risks associated with the
relatively short life span of the t:slim product, or tell us why you do not believe such
disclosure is required.

Our financial performance..., p age 32

15. With a view toward disclosure, please explain the basis for your belief that the t:slim
product is not subject to the 2.3% annual excise tax  on medical devices .

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
September 6, 2013
Page 4

Use of Proceeds, page 41

16. Please refer to Regulation S -K, Item 504 and revise to dis close the approximate dollar
amount of proceeds intended for each stated purpose.

Capitalization, page 43

17. Please revise to  remove  cash and cash equivalents from the table on page 43 since this is
not a component of capitalization for purposes of this disclosure .

Management’s Discussion and Analysis, starting on page 48

Comparison of Six Months…, page 50

18. Please revise to disclose what portion of your revenues was derived from pump -related
supplies and accessories .  Please also disclos e whether your margins for pump -related
supplies an d accessories materially differ  from your t:slim margins.

Liquidity and Capital Resources, page 52

19. Please revise to disclose your estimated working capital needs and capital expenditures
over the next year and discuss plans to fund your liquidity requirements.

Contractual Obligations and Commitments, page 55

20. We note your disclosure prior to the table that s ubsequent to fiscal year end, you entered
into the term loan agreement with Capital Royalty Partners.  Please revise to quantify,
either with the statement prior to the table , by footnote to the table or otherwise, the
payments due to Capital Royalty Partn ers for the periods presented in the table.

Critical Accounting Policies and Management Estimates and Assumptions

Stock Based Compensation, pages 57 -61

21. We reference the discussion on pages 57 -60 of the use of third -party valuation specialists
for the valuation of capitalized intellectual property, common stock and option grants .
Please tell us the extent of the reliance that that  you placed on the work of  the third party
specialists . In that regard, please tell us how  you consid ered Qu estion 141.02 of  the
Comp liance and Dis closure Interpretations on  Securities Act Sections, whi ch can be
found at http://www.sec.gov/divisions/corpfin/guidance/sasinterp.htm.

22. Please tell us whether you have had any preliminary pricing discussions with your
underwriters.  If so, please tell us about the substance of those discussions and whether
they were considered in determining the estimated fair value of your common stock.

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
September 6, 2013
Page 5

23. After pricing information is available, please revise to provide a specific discussion of
each significant factor contributing to significant difference s between the estimated fair
value of your stock and the estimated IPO price (or pricing range) for the 12 months prior
to the IPO .  Please note that we are deferring final evaluation of share -based
compensation until the estimated offering price is specified, and we may have further
comments in that regard when you file an amendment containing that information.

24. Please explain how you determined the estimated fair value of $15 per share in January
2012 through July 2012.  We note that the convertible preferred stock issuances were at a
significantly lower price.  In addition, further clarify the reason that the estima ted fair
value per common share was lowered to $2.96 in March 2013. Please explain the specific
developments and circumstances that resulted in a significantly lower valuation.

25. Please disclose how you considered the convertible preferred stock issuances in fiscal
2012 and 2013 in the valuation of your common shares.  We note that the preferred
issuances were at $4.40 per share in fiscal 2012 and 2013 and that the estimated value of
common shares during this period from page 61 was significantly different. We also note
that preferred shares convert to an equal number of common shares.

Our Solution, page 67

26. In an appropriate section of your document, please balance your disclosure regarding the
advantages of your technology with any material challenges of the technology.  In this
regard, we note the disadvantages section of the table on page 64 is provided as
comparison between injections and pumps generally, and is not specific to your
technology compared with traditional injection therapy or other insulin pumps.

Sales and Marketing, page 75

27. We note your disclosure on page F -10 indicating that you have cus tomers that accounted
for greater than 10% of your revenues.  Please revise your disclosure to identify these
customers.  Refer to Regulation S -K, Item 101(c)(1)(vii).

Third -Party Reimbursement, page 77

28. We note your disclosure on page 77 indicating that your products are described by
existing codes for Medicare reimbursement and your disclosure on page 11 that many
third -party payors look to CMS coverage determinations when setting their own coverage
policies.  Accordingly, please expand your disclosure to address existing CMS
reimbursement coverage for insulin pumps and disposable cartridges and discuss any
trends related to CMS reimbursement policies.

29. We refer to your disclosure on page 4 concerning you r intent to add third -party payors
and your disclosure on page 12 indicating that traditional insulin pump suppliers enjoy

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
September 6, 2013
Page 6

 competitive advantages because they have established relationships with healthcare
providers and third -party payors.  Accordingly, pl ease expand your discussion of third -
party reimbursement to compare the size of your third -party payor coverage relative to
that of your competitors’.  Also, we note that your disclosure on page 70 indicates that
there are “areas where you have concentrate d (y)our initial sales.”  Accordingly, please
expand your disclosure, as applicable, to identify geographic regions, market segments or
other areas where you have concentrated your initial sales efforts .

Research and Development, page 78

30. Please expand y our discussion of the agreements with DexCom and JDRF to describe
more fully the payment provisions of the agreement s.  For instance, describe and quantify
the milestone payments and clarify whether the license s provide  for royalty payments .  If
so, please  quantify.  Finally, please clarify the intellectual property status of any products
jointly developed with JDRF.

Clinical Advisory Board, page 79

31. Please expand your disclosure to clarify how members of the board are compensated.

Intellectual Property, page 79

32. We note your risk factor disclosure on page 25 indicating that two U.S. patents and
various other pending patents are particularly important to the pumping mechanism and
therefore the functionality of your products.  Please revise your d isclosure on page 79 to
specifically identify the particular patents and patents pending referenced in the risk
factor.

33. Please expand the third paragraph of this section to identify the entity or person with
whom you entered into the agreements mentione d here and specify the technology and
products to which these agreements relate. Also disclose the royalty rate for any
sublicenses that you may enter into that will be payable under the agreement, and clarify
whether you have entered into any sublicenses .

FDA’s Pre -Market Clearance and Approval Requirements, page 80

34. Please revise your disclosure in the second paragraph under this subheading to clarify the
classification of the t:slim  and t:connect products for which you received FDA clearance.
Further identify the classification of the t:flex device for which you plan to submit a
510(k) application and the joint t:slim/DexCom product for which you plan to submit a
PMA application, as  noted on page 81.

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
September 6, 2013
Page 7

Board of Directors, page 92

35. We note your risk factor disclosure on page 32 indicating that following the offering your
executive officers, directors and 5% holders may be able to determine the outcome of all
maters submitted to shareholders.  To the extent that you will satisfy the c riteria
necessary to elect treatment as a “controlled company” pursuant to NASDAQ listing
rules, please revise your disclosure to discuss how this exemption could impact your
corporate governance.

Market Comparisons, page 98

36. Please expand your disclosu re to identify the companies within the peer group you
reference.

Equity -Based Awards, page 99

37. Please expand your narrative disclosure to discuss any grants of awards to named
executive officers after December 31, 2012.

Description of Capital Stock, page 111

38. Your disclosure may not be qualified by reference to state law. Please revise accordingly.

Shares Eligible for Future Sale, page 118

39. Please quantify the number of shares outstanding after the completion of the offering that
will be subject to the lockup agreements and/or Rule 144 restrictions.

Financial Statements

40. Please update the financial statements when requ