TNDM: Leadership change

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. On May 11, 2026, Mark Novara, the Executive Vice President and Chief Commercial Officer of Tandem Diabetes Care, Inc. (the “Company”), was notified that his employment with the Company is being terminated without cause. Mr. Novara’s last day of employment with the Company is scheduled to be May 18, 2026. The Company’s strategy and 2026 goals remain unchanged. 2 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Tandem Diabetes Care, Inc. By: /s/ SHANNON M. HANSEN Shannon M. Hansen Executive Vice President, Chief Legal, Privacy & Compliance Officer and Secretary Date: May 15, 2026 3