Christopher J. Twomey - 20 May 2026 Form 4 Insider Report for TANDEM DIABETES CARE INC (TNDM)

Reporting relationship: Director
Issuer ticker: TNDM
Reported as of: 20 May 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 22 May 2026, 16:06:15 UTC
Prior SEC filing: 14 May 2026
Source filing: View source filing
Reporting owner signature: /s/ Jerilyn Laskie, Attorney-in-Fact for Christopher J. Twomey

Key filing fact

Christopher J. Twomey filed Form 4 for TANDEM DIABETES CARE INC (TNDM) on 22 May 2026.

Key facts

This page summarizes Christopher J. Twomey's Form 4 filing for TANDEM DIABETES CARE INC (TNDM).
3 reported transactions and 2 derivative rows are listed below.
Accepted by SEC: 22 May 2026, 16:06.

Change

Previous filing in this sequence was filed on 14 May 2026.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001238935 Primary reporting owner

TWOMEY CHRISTOPHER J

Relationship: Director
Address: 12400 HIGH BLUFF DRIVE, SAN DIEGO
Signature: /s/ Jerilyn Laskie, Attorney-in-Fact for Christopher J. Twomey
Signature date: 22 May 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

TNDM transaction

Common Stock

Options Exercise

Transaction value
Shares: +8,759
Change %: +56%
Price: $0.000000^*
Shares after: 24,434
Date: 21 May 2026
Ownership: Direct

TNDM holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 5,112
Date: 20 May 2026
Ownership: See Footnote
Footnotes: F1

TNDM holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 7,568
Date: 20 May 2026
Ownership: See Footnotes
Footnotes: F2

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

TNDM transaction Derivative

Restricted Stock Unit

Award

Transaction value
Shares: +10,220
Change %
Price: $0.000000^*
Shares after: 10,220
Date: 20 May 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 10,220
Exercise price
Footnotes: F3, F4

TNDM transaction Derivative

Restricted Stock Unit

Options Exercise

Transaction value
Shares: -8,759
Change %: -100%
Price: $0.000000^*
Shares after: 0
Date: 21 May 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 8,759
Exercise price
Footnotes: F3, F5

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 5 footnotes

Footnote F1

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

Footnote F2

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.

Footnote F3

Each restricted stock units (RSU) represents a contingent right to receive either one share of the Issuers common stock or cash in lieu thereof, at the Issuers discretion, in accordance with the terms of the Tandem Diabetes Care, Inc. 2023 Long-Term Incentive Plan, as amended, and agreements related thereto (the 2023 Plan).

Footnote F4

RSU will vest on the one-year anniversary of the grant date, subject to the terms of the 2023 Plan.

Footnote F5

On May 21, 2025, the Reporting Person was granted 8,759 RSUs, all of which vested and converted into shares of the Issuers common stock on the one-year anniversary thereof in accordance with the 2023 Plan.

SEC remarks

Ex. 24: Power of Attorney