Leigh Vosseller - Nov 17, 2025 Form 4 Insider Report for TANDEM DIABETES CARE INC (TNDM)

Role
EVP & CHIEF FINANCIAL OFFICER
Signature
/s/ Shannon M. Hansen, Attorney-in-Fact for Leigh A. Vosseller
Stock symbol
TNDM
Transactions as of
Nov 17, 2025
Transactions value $
-$19,987
Form type
4
Date filed
11/19/2025, 04:06 PM
Previous filing
Aug 19, 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Vosseller Leigh EVP & CHIEF FINANCIAL OFFICER 12400 HIGH BLUFF DRIVE, SAN DIEGO /s/ Shannon M. Hansen, Attorney-in-Fact for Leigh A. Vosseller 2025-11-19 0001726322

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction TNDM Common Stock Options Exercise $0 +1.5K +4.21% $0.00 37.2K Nov 17, 2025 Direct
transaction TNDM Common Stock Tax liability -$10K -538 -1.45% $18.61 36.7K Nov 17, 2025 Direct F1
transaction TNDM Common Stock Options Exercise $0 +1.5K +4.08% $0.00 38.2K Nov 17, 2025 Direct
transaction TNDM Common Stock Tax liability -$9.97K -536 -1.4% $18.61 37.6K Nov 17, 2025 Direct F1
holding TNDM Common Stock 25.6K Nov 17, 2025 Leigh A. Vosseller Trust F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction TNDM Restricted Stock Unit Options Exercise $0 -1.5K -33.33% $0.00 3.01K Nov 17, 2025 Common Stock 1.5K Direct F3, F4, F5
transaction TNDM Restricted Stock Unit Options Exercise $0 -1.5K -14.29% $0.00 8.97K Nov 17, 2025 Common Stock 1.5K Direct F4, F6, F7
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 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.
F2 The securities are held by the Leigh A. Vosseller Trust dated January 17, 2010, of which Leigh Vosseller is the Trustee.
F3 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).
F4 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.
F5 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.
F6 Awarded on May 23, 2024 pursuant to the 2023 Plan.
F7 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.