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Tandem Diabetes Care (TNDM) CEO reports RSU vesting, ESPP buy and tax withholding

Filing Impact
(Neutral)
Filing Sentiment
(Neutral)
Form Type
4

Rhea-AI Filing Summary

Tandem Diabetes Care President and CEO John F. Sheridan reported routine equity compensation activity in common stock. On May 15, 2026, he acquired 1,336 shares at $10.90 per share through the company’s Employee Stock Purchase Plan. Several restricted stock unit awards vested and were exercised into a total of 51,189 shares of common stock. To cover related tax obligations, 24,773 shares were withheld by the company at $12.82 per share, and the footnotes state that no shares were sold on the market.

Positive

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Insider Sheridan John F
Role PRESIDENT & CEO
Type Security Shares Price Value
Exercise Restricted Stock Unit 5,472 $0.00 --
Exercise Restricted Stock Unit 5,982 $0.00 --
Exercise Restricted Stock Unit 39,735 $0.00 --
Exercise Common Stock 5,472 $0.00 --
Tax Withholding Common Stock 2,785 $12.82 $36K
Exercise Common Stock 5,982 $0.00 --
Tax Withholding Common Stock 3,044 $12.82 $39K
Exercise Common Stock 39,735 $0.00 --
Tax Withholding Common Stock 18,944 $12.82 $243K
Grant/Award Common Stock 1,336 $10.90 $15K
Holdings After Transaction: Restricted Stock Unit — 0 shares (Direct, null); Common Stock — 130,163 shares (Direct, null)
Footnotes (1)
  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. The reporting person is voluntarily reporting the acquisition of shares of common stock pursuant to the Tandem Diabetes Care, Inc. Amended and Restated 2013 Employee Stock Purchase Plan (ESPP), for the ESPP purchase period of November 18, 2025, through May 15, 2026. This transaction is also exempt under Rule 16b-3(c). 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). Each restricted stock unit (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. 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. Awarded on May 23, 2024 pursuant to the 2023 Plan, as amended. 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. Awarded on May 30, 2025 pursuant to the 2023 Plan. RSU vest as to thirty-three percent (33%) of the total number of shares subject to the RSU on 5/15/2026, and the remaining shares shall vest in eight (8) equal quarterly installments thereafter.
ESPP shares acquired 1,336 shares Common stock purchased at $10.90 per share via ESPP on May 15, 2026
ESPP purchase price $10.90/share Price for ESPP acquisition of 1,336 common shares
RSU exercises 51,189 shares Total common shares from derivative exercises (transactionSummary exerciseShares)
Tax-withholding shares 24,773 shares Shares withheld to satisfy tax obligations on vesting (F-code transactions)
Tax-withholding price $12.82/share Price applied to shares withheld for tax withholding dispositions
Exercise transactions 3 exercises Number of derivative exercise or conversion transactions (M-code) in summary
Restricted Stock Unit financial
"security_title: "Restricted Stock Unit" with underlying common stock"
A restricted stock unit is a promise from a company to give an employee shares of stock after certain conditions are met, like staying with the company for a set amount of time. It’s like earning a bonus that turns into company stock once you’ve proven your commitment, making it a way to motivate and reward employees.
Employee Stock Purchase Plan financial
"acquisition of common stock pursuant to the Amended and Restated 2013 Employee Stock Purchase Plan"
An employee stock purchase plan is a company program that lets workers buy shares through small payroll deductions, often at a discount to the market price and after a set offering period. Think of it like a workplace savings plan that turns into ownership: it encourages employees to share in the company’s success and can create predictable buying or selling of stock that investors watch because it affects supply, demand and employee incentives.
tax withholding requirements financial
"Shares withheld by Tandem Diabetes Care Inc. to satisfy tax withholding requirements on vesting of restricted stock units"
Rule 16b-3(c) regulatory
"This transaction is also exempt under Rule 16b-3(c)"
An SEC rule that lets corporate insiders avoid automatic "short‑swing" profit recovery when they buy or sell their company’s stock under a pre‑approved, written plan that meets specific conditions. For investors, it matters because it clarifies when insider trades are treated as routine, reducing legal uncertainty and helping distinguish trades made for ordinary compensation or pre‑planned reasons from those that might signal opportunistic or timely insider advantage.
Long-Term Incentive Plan financial
"Awarded on May 25, 2023 pursuant to the Tandem Diabetes Care Inc. 2023 Long-Term Incentive Plan"
A long-term incentive plan is a company program that pays executives or employees with stock, options, or cash tied to multi-year performance goals, where the rewards become theirs only after meeting conditions over time. Think of it as a delayed bonus or retirement-style reward that aligns employees’ interests with shareholders by encouraging them to boost long-term value; investors watch these plans because they affect pay costs, share dilution and management incentives.
SEC Form 4
FORM 4UNITED 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).
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 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)
XDirector10% Owner
XOfficer (give title below)Other (specify below)
PRESIDENT & CEO
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
05/15/2026
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm 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)
CodeVAmount(A) or (D)Price
Common Stock05/15/2026M5,472A$0130,163D
Common Stock05/15/2026F(1)2,785D$12.82127,378D
Common Stock05/15/2026M5,982A$0133,360D
Common Stock05/15/2026F(1)3,044D$12.82130,316D
Common Stock05/15/2026M39,735A$0170,051D
Common Stock05/15/2026F(1)18,944D$12.82151,107D
Common Stock05/15/2026A(2)1,336A$10.9152,443D
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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Restricted Stock Unit(3)(4)05/15/2026M5,472 (5) (5)Common Stock5,472$00D
Restricted Stock Unit(6)(4)05/15/2026M5,982 (7) (7)Common Stock5,982$023,929D
Restricted Stock Unit(8)(4)05/15/2026M39,735 (9) (9)Common Stock39,735$079,471D
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. The reporting person is voluntarily reporting the acquisition of shares of common stock pursuant to the Tandem Diabetes Care, Inc. Amended and Restated 2013 Employee Stock Purchase Plan (ESPP), for the ESPP purchase period of November 18, 2025, through May 15, 2026. This transaction is also exempt under Rule 16b-3(c).
3. 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).
4. Each restricted stock unit (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.
5. 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.
6. Awarded on May 23, 2024 pursuant to the 2023 Plan, as amended.
7. 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.
8. Awarded on May 30, 2025 pursuant to the 2023 Plan.
9. RSU vest as to thirty-three percent (33%) of the total number of shares subject to the RSU on 5/15/2026, and the remaining shares shall vest in eight (8) equal quarterly installments thereafter.
Remarks:
/s/ Shannon M. Hansen, Attorney-in-Fact for John F. Sheridan05/19/2026
** Signature of Reporting PersonDate
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)

FAQ

What insider transactions did TNDM CEO John F. Sheridan report on May 15, 2026?

John F. Sheridan reported equity compensation activity on May 15, 2026, including ESPP purchases and RSU vesting. He exercised restricted stock units into common shares and had a portion withheld to cover taxes, with no market sales disclosed in this filing.

How many Tandem Diabetes Care (TNDM) shares did the CEO acquire via ESPP?

The CEO acquired 1,336 shares of Tandem Diabetes Care common stock at $10.90 per share through the Amended and Restated 2013 Employee Stock Purchase Plan covering the purchase period from November 18, 2025, through May 15, 2026, as described in the footnotes.

Were any Tandem Diabetes Care (TNDM) shares sold by the CEO in this filing?

No market sales were reported in this Form 4. Shares labeled with transaction code F were withheld by Tandem Diabetes Care to satisfy tax withholding requirements upon RSU vesting, and the footnotes explicitly state that no shares were sold in these transactions.

Why were some TNDM shares marked as tax-withholding dispositions in the CEO’s Form 4?

Shares coded F were withheld to pay tax obligations triggered by RSU vesting and related exercises. The company retained 24,773 shares at $12.82 per share for this purpose, which is treated as a tax-withholding disposition rather than an open-market sale by the CEO.

What plans governed the Tandem Diabetes Care (TNDM) equity awards in this Form 4?

The transactions involve equity granted under the Tandem Diabetes Care 2023 Long-Term Incentive Plan and shares acquired through the Amended and Restated 2013 Employee Stock Purchase Plan. Footnotes also reference exemptions under Rule 16b-3(c) for these compensation-related acquisitions.