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

Rhea-AI Filing Summary

Susan M. Morrison, EVP & Chief Administrative Officer of Tandem Diabetes Care, Inc. (TNDM), reported equity transactions dated 08/15/2025 on Form 4. The filing shows vesting of restricted stock units (RSUs) awarded under the 2023 Long-Term Incentive Plan: 1,503 RSUs and 1,097 RSUs were settled (transaction code M) with an acquisition price of $0 for each award. To satisfy tax withholding on the vesting, the company withheld 430 and 314 shares respectively at a withholding price of $10.82 per share; the filer states explicitly that no shares were sold. The Form indicates the transactions were reported by an attorney-in-fact on 08/19/2025. The filing itemizes the share movements and confirms the RSU grant and vesting schedule terms referenced in the explanation section of the Form.

Insights

Financial Analyst

TL;DR: Routine RSU vesting with withholding for taxes; no sales reported, minimal near-term market impact.

The Form 4 documents standard compensation settlement activity: two RSU tranches vested resulting in 1,503 and 1,097 shares acquired at $0, with 430 and 314 shares withheld to satisfy tax obligations at $10.82 per share.

This activity represents executive compensation realization rather than open-market disposition, and the filer states that no shares were sold, limiting immediate dilution or market selling pressure. The transactions are consistent with the company’s disclosed LTIP vesting schedule and thus are routine from a financial reporting perspective.

Corporate Governance Expert

TL;DR: Governance-standard execution of equity compensation; withholding used for tax compliance, substitutions align with plan terms.

The filing cites RSUs awarded under the 2023 Long-Term Incentive Plan and explains vesting timing and settlement mechanics. Withholding of 430 and 314 shares for tax purposes is explicitly disclosed and the filer affirms no open-market sales occurred. The Form appears complete for the reported transactions and includes a signed attorney-in-fact filing, which satisfies procedural requirements for Section 16 reporting.

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

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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^*

Morrison Susan

(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 Admin. 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	38,709	D
Common Stock	08/15/2025		F(1)		430	D	$10.82	38,279	D
Common Stock	08/15/2025		M		1,097	A	$0	39,376	D
Common Stock	08/15/2025		F(1)		314	D	$10.82	39,062	D

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(2)	(3)	08/15/2025		M			1,503	(4)	(4)	Common Stock	1,503	$0	4,509	D
Restricted Stock Unit(5)	(3)	08/15/2025		M			1,097	(6)	(6)	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. Awarded on May 25, 2023 pursuant to the Tandem Diabetes Care, Inc. 2023 Long-Term Incentive Plan (the 2023 Plan).

3. 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.

4. 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.

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

6. 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 Susan M. Morrison	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).
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FAQ

What transactions did Susan M. Morrison report on Form 4 for TNDM?

The Form 4 reports RSU vesting on 08/15/2025: 1,503 and 1,097 RSUs were settled; 430 and 314 shares were withheld for taxes at $10.82 per share.

Were any shares sold by the reporting person in this filing (TNDM)?

No. The filing explicitly states no shares were sold; shares were withheld only to satisfy tax withholding requirements.

Under which plan were the RSUs awarded to Susan M. Morrison?

The RSUs were awarded pursuant to the Tandem Diabetes Care, Inc. 2023 Long-Term Incentive Plan as stated in the filing.

What withholding price was used to satisfy taxes on the vested RSUs?

The company withheld shares at a price of $10.82 per share to satisfy tax withholding obligations.

Who filed and signed the Form 4 on behalf of Susan M. Morrison?

The Form 4 was signed and filed by Rachel Malina, Attorney-in-Fact for Susan M. Morrison on 08/19/2025.