[Form 4] Tandem Diabetes Care, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Elizabeth A. Gasser, EVP and Chief Strategy Officer of Tandem Diabetes Care, reported multiple transactions on 08/15/2025 affecting her holdings of TNDM common stock. She acquired 1,503 shares (RSU vesting) and an additional 1,097 shares (RSU vesting), both reported as acquisitions at $0 per share. To satisfy tax withholding on vesting, 805 and 588 shares were withheld and disposed at $10.82 per share; no shares were sold on the open market. She directly beneficially owns 4,509 shares from vested RSUs and 7,677 shares from other RSUs per the table, and indirectly holds 22,949 shares through The Gasser Family Trust, where she is a co-trustee.

Insights

Financial Analyst

TL;DR: Insider received vested RSUs and had shares withheld for taxes; overall holdings rose modestly with substantial indirect trust ownership.

These entries show routine executive compensation mechanics: two RSU vesting events produced 2,600 shares acquired and triggered withholding of 1,393 shares to cover taxes at $10.82 per share. The transactions are consistent with plan terms and do not indicate open-market sales. Indirect ownership of 22,949 shares via a family trust represents a meaningful ownership stake relative to the direct holdings disclosed here, reinforcing ongoing alignment with shareholders.

Corporate Governance Expert

TL;DR: Transactions reflect standard equity compensation vesting and tax withholding; disclosures identify trust holdings and filing compliance.

The Form 4 clearly discloses vesting schedules and the tax-withholding mechanism, including citations to the 2023 Long-Term Incentive Plan. The reporting was filed by an attorney-in-fact and includes explanatory footnotes about the trust. No departures, option exercises for cash proceeds, or unusual dispositions are reported, indicating routine governance and disclosure practices.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Gasser Elizabeth Anne

(Last) (First) (Middle)

12400 HIGH BLUFF DRIVE

(Street)

SAN DIEGO CA 92130

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
TANDEM DIABETES CARE INC [ TNDM ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP, Chief Strategy Officer

3. Date of Earliest Transaction (Month/Day/Year)
08/15/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	08/15/2025		M		1,503	A	$0	1,503	D
Common Stock	08/15/2025		F		805(1)	D	$10.82	698	D
Common Stock	08/15/2025		M		1,097	A	$0	1,795	D
Common Stock	08/15/2025		F		588(1)	D	$10.82	1,207	D
Common Stock								22,949	I	See Footnote(2)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Unit(3)	(4)	08/15/2025		M			1,503	(5)	(5)	Common Stock	1,503	$0	4,509	D
Restricted Stock Unit(6)	(4)	08/15/2025		M			1,097	(7)	(7)	Common Stock	1,097	$0	7,677	D

Explanation of Responses:

1. Shares withheld by Tandem Diabetes Care, Inc. (the Company) to satisfy tax withholding requirements on vesting of restricted stock units (RSU). No shares were sold.

2. The securities are held by The Gasser Family Trust dated September 1, 2011, of which Elizabeth A. Gasser is a co-trustee.

3. Awarded on May 25, 2023 pursuant to the Tandem Diabetes Care, Inc. 2023 Long-Term Incentive Plan, as amended, and agreements related thereto (the 2023 Plan).

4. Each RSU represents a contingent right to receive either one share of common stock of the Issuer or cash in lieu thereof, at the Issuer's discretion, in accordance with the terms of the 2023 Plan.

5. RSU vest as to thirty-three percent (33%) of the total number of shares subject to the RSU on 5/15/2024, and the remaining shares shall vest in eight (8) equal quarterly installments thereafter.

6. Awarded on May 23, 2024 pursuant to the 2023 Plan.

7. RSU vest as to thirty-three percent (33%) of the total number of shares subject to the RSU on 5/15/2025, and the remaining shares shall vest in eight (8) equal quarterly installments thereafter.

Remarks:

	/s/ Rachel Malina, Attorney-in-Fact for Elizabeth A. Gasser	08/19/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.