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

Rhea-AI Filing Summary

John F. Sheridan, President & CEO and director of Tandem Diabetes Care, Inc. (TNDM), reported RSU vesting and related share withholding to cover taxes on transactions dated 08/15/2025. The filing shows vested restricted stock units (RSUs) settled into 5,471 and 5,982 shares respectively, increasing underlying ownership; the company withheld 2,779 and 3,038 shares in two separate withholding dispositions at $10.82 per share to satisfy tax obligations. After these transactions, Sheridan beneficially owned between 109,019 and 115,001 shares across reported lines. The RSUs were awarded under the 2023 Long-Term Incentive Plan and vest per the schedules described in the filing.

Positive

• Continued alignment of management with shareholders via equity compensation vesting under the 2023 Long-Term Incentive Plan
• No evidence of opportunistic open-market selling; dispositions were share-withholdings to satisfy taxes

Negative

• Shares withheld at $10.82 reduced the reported post-transaction share counts by 2,779 and 3,038 shares
• Form 4 does not disclose any open-market purchases that would increase insider ownership beyond RSU settlement

Insights

Corporate Governance Expert

TL;DR: Routine executive RSU vesting with tax-withholding share dispositions; no new cash sales beyond withholding indicated.

The Form 4 documents standard equity compensation mechanics: RSUs awarded in 2023 and 2024 vested and were settled on 08/15/2025, producing both share increases and withholding dispositions to cover taxes at $10.82 per share. There is no indication of additional open-market sales or changes in insider status. For governance, these are typical actions under the company equity plan and do not by themselves signal a change in management intent or control.

Securities Analyst

TL;DR: Vesting-related share settlements and tax-withholdings are disclosed; impact on outstanding shares is limited and administrative.

The transactions include RSU settlement (codes M) and withholding dispositions (code F) executed to satisfy tax obligations. Reported prices for withheld shares are $10.82, and no additional cash proceeds or discretionary sales are shown. The net effect is a transfer from plan-based derivative holdings into common stock ownership with partial reduction via withholding; this is routine and unlikely to materially affect shareholder value.

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
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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)
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		5,471	A	$0	111,798	D
Common Stock	08/15/2025		F(1)		2,779	D	$10.82	109,019	D
Common Stock	08/15/2025		M		5,982	A	$0	115,001	D
Common Stock	08/15/2025		F(1)		3,038	D	$10.82	111,963	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			5,471	(4)	(4)	Common Stock	5,471	$0	16,415	D
Restricted Stock Unit(5)	(3)	08/15/2025		M			5,982	(6)	(6)	Common Stock	5,982	$0	41,876	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/ Rachel Malina, Attorney-in-Fact for John F. Sheridan	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.
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FAQ

What transactions did John F. Sheridan report on the TNDM Form 4?

The filing reports RSU settlements (resulting in 5,471 and 5,982 shares) and withholding dispositions of 2,779 and 3,038 shares to satisfy taxes.

Were any shares sold on the open market by John F. Sheridan (TNDM)?

No open-market sales are reported; the dispositions are described as shares withheld by the company to satisfy tax withholding requirements.

At what price were shares withheld for taxes in the TNDM Form 4?

$10.82 per share for the withholding dispositions shown.

How many TNDM shares did Sheridan beneficially own after the reported transactions?

Reported beneficial ownership amounts following transactions range from 109,019 to 115,001 shares across the reported lines.

Under what plan were the RSUs awarded to John F. Sheridan?

The RSUs were awarded under the Tandem Diabetes Care, Inc. 2023 Long-Term Incentive Plan (the 2023 Plan).