Tandem Diabetes Care director sells 1,700 shares

The director’s indirect holdings included 7,568 shares through Twomey Family Investments, LLC and 5,112 shares through the Chris J. Twomey and Rebecca J. Twomey Family Trust.

Rhea-AI Filing Summary

Tandem Diabetes Care Inc. (TNDM) director Christopher J. Twomey exercised 1,700 stock options on October 27, 2026, at a $19.00 exercise price, acquiring 1,700 common shares; he sold 1,700 shares at $19.15 per share that day. The sale was made under a Rule 10b5-1 trading plan adopted May 19, 2026. Indirect holdings listed on October 27, 2026 included 7,568 shares held by Twomey Family Investments, LLC, where Twomey is co-manager and shares voting and investment power, and 5,112 shares held by the Chris J. Twomey and Rebecca J. Twomey Family Trust, dated September 20, 2002.

Insider Trade Summary 10b5-1

Exercise and Sale: 1,700 shares ($255.00 approx. pre-tax spread)

Exercise and Sale 5 txns

Insider TWOMEY CHRISTOPHER J

Role Director

Sold 1,700 shs ($33K)

Approx. gross sale proceeds $33K

Approx. exercise cost $32K

Approx. pre-tax spread $255.00

Type	Security	Shares	Price	Value
Exercise	Stock Option F5, F6, F7	1,700	$0.00	$0.00
Exercise	Common Stock F1	1,700	$19.00	$32K
Sale	Common Stock F2	1,700	$19.15	$33K
holding	Common Stock F3	--	--	--
holding	Common Stock F4	--	--	--

Holdings After Transaction: Stock Option — 0 contracts (Direct); Common Stock — 24,434 shares (Direct); Common Stock — 7,568 shares (Indirect, See Footnotes); Common Stock — 5,112 shares (Indirect, See Footnote)

Footnotes (7)

1. F1. Represents shares of common stock received upon exercise of a stock option award.
2. F2. The shares were sold pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 19, 2026.
3. F3. The securities are directly owned by Twomey Family Investments, LLC. The Reporting Person is co-manager of Twomey Family Investments, LLC and shares voting and investment power over these securities held by Twomey Family Investments, LLC and may be deemed to have indirect beneficial ownership of such shares. The Reporting Person disclaims beneficial ownership of such securities held by Twomey Family Investments, LLC, except to the extent of his proportionate pecuniary interest therein.
4. F4. The securities are held by the Chris J. Twomey and Rebecca J. Twomey Family Trust UTD September 20, 2002.
5. F5. Awarded on November 15, 2016 pursuant to the Tandem Diabetes Care, Inc. 2013 Stock Incentive Plan, as amended, and the agreements related thereto.
6. F6. Such options became exercisable in 12 equal monthly installments beginning on December 15, 2016.
7. F7. Such options expire on November 15, 2026.

Key Figures

Stock options exercised: 1,700 options Exercise price: $19.00 per share Common shares acquired: 1,700 shares +4 more

7 metrics

Stock options exercised 1,700 options October 27, 2026

Exercise price $19.00 per share Options exercised October 27, 2026

Common shares acquired 1,700 shares Upon option exercise on October 27, 2026

Sale price $19.15 per share October 27, 2026

Common shares sold 1,700 shares October 27, 2026

Indirect shares held by Twomey Family Investments, LLC 7,568 shares Listed October 27, 2026

Indirect shares held by the Chris J. Twomey and Rebecca J. Twomey Family Trust 5,112 shares Listed October 27, 2026

Key Terms

Rule 10b5-1 trading plan, stock option award, indirect beneficial ownership

3 terms

Rule 10b5-1 trading plan regulatory

"sold pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

stock option award financial

"shares of common stock received upon exercise of a stock option award"

A stock option award is a grant that gives an employee the right to buy a company’s shares at a fixed price for a limited time, often becoming available gradually over a set schedule. Investors care because these awards align workers’ incentives with company performance, can increase employee loyalty, and may create future share dilution and compensation expense that affect earnings per share and shareholder value.

indirect beneficial ownership financial

"may be deemed to have indirect beneficial ownership of such shares"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many TNDM shares did director Christopher J. Twomey sell, and at what price?

Christopher J. Twomey, a Tandem Diabetes Care director, sold 1,700 common shares at $19.15 per share on October 27, 2026. He had exercised options to acquire 1,700 shares at $19.00 per share that day.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 10/29/2026 - 04:07 PM EDT Accepted by SEC EDGAR 10/29/2026 - 04:06 PM EDT Learn about SEC filing dates

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).

X

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^*

TWOMEY CHRISTOPHER J

(Last) (First) (Middle)

12400 HIGH BLUFF DRIVE

(Street)

SAN DIEGO CALIFORNIA 92130

(City) (State) (Zip)

UNITED STATES

(Country)

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
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
10/27/2026

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

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

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

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	10/27/2026		M(1)		1,700	A	$19	26,134	D
Common Stock	10/27/2026		S(2)		1,700	D	$19.15	24,434	D
Common Stock								7,568	I	See Footnotes(3)
Common Stock								5,112	I	See Footnote(4)

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
Stock Option(5)	$19	10/27/2026		M			1,700	(6)	(7)	Common Stock	1,700	$0	0	D

Explanation of Responses:

1. Represents shares of common stock received upon exercise of a stock option award.

2. The shares were sold pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 19, 2026.

3. The securities are directly owned by Twomey Family Investments, LLC. The Reporting Person is co-manager of Twomey Family Investments, LLC and shares voting and investment power over these securities held by Twomey Family Investments, LLC and may be deemed to have indirect beneficial ownership of such shares. The Reporting Person disclaims beneficial ownership of such securities held by Twomey Family Investments, LLC, except to the extent of his proportionate pecuniary interest therein.

4. The securities are held by the Chris J. Twomey and Rebecca J. Twomey Family Trust UTD September 20, 2002.

5. Awarded on November 15, 2016 pursuant to the Tandem Diabetes Care, Inc. 2013 Stock Incentive Plan, as amended, and the agreements related thereto.

6. Such options became exercisable in 12 equal monthly installments beginning on December 15, 2016.

7. Such options expire on November 15, 2026.

Remarks:

	/s/ Jerilyn Laskie, Attorney-in-Fact for Christopher J. Twomey	10/29/2026
	** 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.
* Form 4: SEC 1474 (03-26)