Initial Registration Statement for Employee Benefit Plan (Form S-8)

As Filed With the Securities and Exchange Commission on May 27, 2026

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington D.C. 20549

____________________________

FORM S-8

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

____________________________

Tandem Diabetes Care, Inc.

(Exact name of registrant as specified in its charter)

Delaware			20-4327508
(State or other jurisdiction of incorporation or organization)			(I.R.S. Employer Identification No.)
12400 High Bluff Drive, San Diego, CA			92130
(Address of principal executive offices)			(Zip Code)

__________________________

Tandem Diabetes Care, Inc. 2023 Long-Term Incentive Plan

(Full title of the plan)

Shannon M. Hansen

Tandem Diabetes Care, Inc.

Executive Vice President, Chief Legal, Privacy & Compliance Officer and Secretary

(Name and address of agent for service)

(858) 366-6900

(Telephone number, including area code, of agent for service)

____________________________

Copies to:

Charles J. Bair

Asa M. Henin

Cooley LLP

10265 Science Center Drive

San Diego, California 92121

Tel: (858) 550-6000

____________________________

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

Large accelerated filer

x

Accelerated filer

☐

Non-accelerated filer

☐

Smaller reporting company

☐

Emerging growth company

☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.

REGISTRATION OF ADDITIONAL SHARES

PURSUANT TO GENERAL INSTRUCTION E

This Registration Statement on Form S-8 (this Registration Statement) is being filed by Tandem Diabetes Care, Inc. (the Registrant) for the purpose of registering an additional 3,260,000 shares of common stock, par value $0.001 per share, of the Registrant (the Additional Shares) that became issuable under the Tandem Diabetes Care, Inc. 2023 Long-Term Incentive Plan, as amended (the Plan).

The Additional Shares are securities of the same class as other securities for which previous Registration Statements on Form S-8 were filed by the Registrant with the U.S. Securities and Exchange Commission (the SEC) on August 3, 2023 (File No. 333-273648) and May 23, 2024 (File No. 333-279642) (together, the Prior Registration Statements).

Pursuant to General Instruction E to Form S-8, this Registration Statement hereby incorporates by reference the contents of the Prior Registration Statements.

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

The following documents filed by the Registrant with the SEC are incorporated by reference into this Registration Statement:

(a) The Registrant's Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the SEC on February 19, 2026 (the 2025 10-K);

(b) The information specifically incorporated by reference into the 2025 10-K from the Registrant's Definitive Proxy Statement on Schedule 14A filed with the SEC on April 7, 2026;

(c) The Registrant's Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2026, filed with the SEC on May 7, 2026;

(d) The Registrant's Current Reports on Form 8-K filed with the SEC on February 27, 2026, May 15, 2026 and May 21, 2026; and

(e) The description of the Registrant's Capital Stock included as Exhibit 4.2 to the 2025 10-K, including any amendments or reports filed for the purpose of updating such description.

All documents, reports, and definitive proxy or information statements filed by the Registrant pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (the Exchange Act), after the date of this Registration Statement and prior to the filing of a post-effective amendment which indicates that all securities offered hereby have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference into this Registration Statement and to be a part hereof from the date of filing of such documents; provided, however, that documents, reports and definitive proxy or information statements, or portions thereof, that are furnished and not filed or are otherwise not incorporated into registration statements filed in accordance with the rules of the SEC, shall not be deemed incorporated by reference into this Registration Statement. Any statement contained in a document incorporated or deemed to be incorporated herein by reference shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein modifies or supersedes that statement. Any such statement so modified or superseded shall not constitute a part of this Registration Statement, except as so modified or superseded.

ITEM 8. EXHIBITS.

Incorporated by Reference

Exhibit Number

Description

Form

File No.

Date of First Filing

Exhibit Number

Provided herewith

4.1

Amended and Restated Certificate of Incorporation of the Registrant (as amended and currently in effect).

8-K

001-36189

May 21, 2026

3.1

4.2

Amended and Restated Bylaws of the Registrant (as amended and currently in effect).

8-K

001-36189

December 30, 2025

3.1

5.1

Opinion of Cooley LLP.

X

23.1						Consent of Independent Registered Public Accounting Firm.																														X
23.2						Consent of Cooley LLP. Reference is made to Exhibit 5.1.																														X
24.1						Power of Attorney. Reference is made to the signature page hereto.																														X
99.1						Tandem Diabetes Care, Inc. 2023 Long-Term Incentive Plan, as amended.						8-K						001-36189						May 21, 2026						10.1
99.2						Form of Restricted Stock Units Agreement under the 2023 Long-Term Incentive Plan.						10-Q						001-36189						August 3, 2023						10.2
107						Filing Fee Table.																														X

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the city of San Diego, State of California.

			Tandem Diabetes Care, Inc.
			By:						/s/ John Sheridan
									John Sheridan
									President and Chief Executive Officer
									(Principal Executive Officer)
Date: May 27, 2026

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints John F. Sheridan and Leigh A. Vosseller, and each of them individually, his and her true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for him and her and in his and her name, place, and stead, in any and all capacities, to sign any and all amendments to this Registration Statement, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or any of them, or his or her substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement on Form S-8 has been signed below by the following persons on behalf of the Registrant and in the capacities and on the dates indicated.

Signature

Title

Date

/s/ JOHN SHERIDAN

President, Chief Executive Officer and Director (Principal Executive Officer)

May 27, 2026

John Sheridan

/s/ LEIGH VOSSELLER

Executive Vice President, Chief Financial Officer and Treasurer (Principal Financial and Accounting Officer)

May 27, 2026

Leigh Vosseller

/s/ REBECCA ROBERTSON

Chair of the Board

May 27, 2026

Rebecca Robertson

/s/ SANDRA BEAVER

Director

May 27, 2026

Sandra Beaver

/s/ MYOUNGIL CHA

Director

May 27, 2026

Myoungil Cha

/s/ PEYTON HOWELL

Director

May 27, 2026

Peyton Howell

/s/ JOAO MALAGUEIRA

Director

May 27, 2026

Joao Malagueira

/s/ KATHLEEN MCGRODDY-GOETZ

Director

May 27, 2026

Kathleen McGroddy-Goetz

/s/ RAJWANT SODHI

Director

May 27, 2026

Rajwant Sodhi

/s/ CHRISTOPHER TWOMEY

Director

May 27, 2026

Christopher Twomey