[Form 4] TANDEM DIABETES CARE INC Insider Trading Activity

Rhea-AI Filing Summary

Tandem Diabetes Care Inc. (TNDM) reported insider equity activity by President & CEO and director John F. Sheridan. On 11/17/2025, restricted stock units (RSUs) granted under the company’s 2023 Long-Term Incentive Plan vested and were settled into common stock at no exercise price.

Following the vesting, 5,472 RSUs and 5,982 RSUs were converted into an equal number of common shares. To cover tax withholding on these RSU vestings, the company withheld 2,779 shares and 3,038 shares at a reference price of $18.61 per share; the filing states that no shares were sold. After these transactions, Sheridan directly owned 117,600 shares of common stock, plus 10,943 RSUs and 35,894 RSUs that remain outstanding and subject to the plan’s vesting schedule.

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^*

Sheridan John F

(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)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	PRESIDENT & CEO

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		5,472	A	$0	117,435	D
Common Stock	11/17/2025		F(1)		2,779	D	$18.61	114,656	D
Common Stock	11/17/2025		M		5,982	A	$0	120,638	D
Common Stock	11/17/2025		F(1)		3,038	D	$18.61	117,600	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			5,472	(4)	(4)	Common Stock	5,472	$0	10,943	D
Restricted Stock Unit(5)	(3)	11/17/2025		M			5,982	(6)	(6)	Common Stock	5,982	$0	35,894	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, as amended.

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 John F. Sheridan	11/19/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transaction did TNDM CEO John F. Sheridan report?

John F. Sheridan reported the vesting and settlement of restricted stock units (RSUs) into common stock of Tandem Diabetes Care Inc. (TNDM) on 11/17/2025, along with related tax withholding share reductions.

How many Tandem Diabetes (TNDM) RSUs vested for the CEO in this Form 4?

On 11/17/2025, 5,472 RSUs from a May 25, 2023 award and 5,982 RSUs from a May 23, 2024 award vested and were converted into common stock in accordance with the 2023 Long-Term Incentive Plan.

Were any TNDM shares sold by the CEO in this filing?

The filing explains that 2,779 shares and 3,038 shares were withheld by Tandem Diabetes Care Inc. to satisfy tax withholding requirements at $18.61 per share, and explicitly states that no shares were sold.

How many Tandem Diabetes (TNDM) shares does the CEO own after these transactions?

After the reported RSU vesting and tax withholding events, John F. Sheridan directly owned 117,600 shares of common stock of Tandem Diabetes Care Inc.

What unvested or outstanding RSUs does the TNDM CEO hold after this Form 4?

Following the transactions, John F. Sheridan beneficially owned 10,943 RSUs from the May 25, 2023 award and 35,894 RSUs from the May 23, 2024 award, each representing a right to receive one share of common stock or cash, per plan terms.

What are the vesting schedules for the TNDM CEO’s RSU awards?

For the May 25, 2023 RSU award, 33% vested on 5/15/2024 and the remainder vests in eight equal quarterly installments thereafter. For the May 23, 2024 RSU award, 33% vests on 5/15/2025 with the balance also vesting in eight equal quarterly installments.