[Form 4] TANDEM DIABETES CARE INC Insider Trading Activity

Rhea-AI Filing Summary

Tandem Diabetes Care Inc. (TNDM) reported equity compensation activity for an executive officer. The EVP & Chief Administrative Officer had restricted stock units (RSUs) convert into common stock on 11/17/2025, with 1,503 and 1,096 RSUs settled into shares at an exercise price of $0.

To cover tax withholding on these vestings, the company withheld 430 and 314 shares at a price of $18.61 per share, and no shares were sold into the market. Following these transactions, the reporting person directly beneficially owned around forty thousand shares of Tandem Diabetes Care common stock.

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)
11/17/2025

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	11/17/2025		M		1,503	A	$0	40,565	D
Common Stock	11/17/2025		F(1)		430	D	$18.61	40,135	D
Common Stock	11/17/2025		M		1,096	A	$0	41,231	D
Common Stock	11/17/2025		F(1)		314	D	$18.61	40,917	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)	11/17/2025		M			1,503	(4)	(4)	Common Stock	1,503	$0	3,006	D
Restricted Stock Unit(5)	(3)	11/17/2025		M			1,096	(6)	(6)	Common Stock	1,096	$0	6,581	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, as amended, and agreements related thereto (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/ Shannon M. Hansen, Attorney-in-Fact for Susan M. Morrison	11/19/2025
	** 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.

FAQ

What insider transaction did Tandem Diabetes Care (TNDM) report on this Form 4?

The filing shows an executive officer had RSUs vest and convert into Tandem Diabetes Care common stock on 11/17/2025, increasing directly held shares.

How many Tandem Diabetes Care RSUs vested for the reporting person?

On 11/17/2025, 1,503 and 1,096 restricted stock units vested and were settled into common shares at an exercise price of $0.

Were any Tandem Diabetes Care (TNDM) shares sold in this Form 4?

No. The explanation states that shares were withheld by the company to satisfy tax withholding requirements on RSU vesting and that no shares were sold.

What were the tax withholding details for the TNDM RSU vesting?

The company withheld 430 and 314 Tandem Diabetes Care shares at a price of $18.61 per share to cover the reporting person’s tax obligations.

What is the reporting person’s role at Tandem Diabetes Care (TNDM)?

The reporting person is listed as an Officer, serving as EVP & Chief Admin. Officer of Tandem Diabetes Care Inc.

From which equity plan did the Tandem Diabetes Care RSUs arise?

The RSU awards were granted under the Tandem Diabetes Care Inc. 2023 Long-Term Incentive Plan, as described in the footnotes.