X0508 4 2025-11-17 0 0001438133 TANDEM DIABETES CARE INC TNDM 0001908267 Hansen Shannon Marie 12400 HIGH BLUFF DRIVE SAN DIEGO CA 92130 0 1 0 0 EVP & Chief Legal Officer 0 Common Stock 2025-11-17 4 A 0 800 15.59 A 19509 D Common Stock 2025-11-17 4 M 0 530 0 A 20039 D Common Stock 2025-11-17 4 F 0 190 18.61 D 19849 D Common Stock 2025-11-17 4 M 0 1437 0 A 21286 D Common Stock 2025-11-17 4 F 0 515 18.61 D 20771 D Common Stock 2025-11-17 4 M 0 1096 0 A 21867 D Common Stock 2025-11-17 4 F 0 393 18.61 D 21474 D Common Stock 1935 I Shannon M. Hansen Trust Restricted Stock Unit 2025-11-17 4 M 0 530 0 D Common Stock 530 531 D Restricted Stock Unit 2025-11-17 4 M 0 1437 0 D Common Stock 1437 2874 D Restricted Stock Unit 2025-11-17 4 M 0 1096 0 D Common Stock 1096 6581 D 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 May 16, 2025, through November 17, 2025. This transaction is also exempt under Rule 16b-3(c). 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 securities are held by the Shannon M. Hansen Trust dated July 8, 2003, of which Shannon M. Hansen is the Trustee. Awarded on February 15, 2022 pursuant to the Tandem Diabetes Care Inc. 2013 Stock Incentive Plan, as amended, and the agreements related thereto (the 2013 Plan). 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 2013 Plan. RSU vest as to twenty-five percent (25%) of the total number of shares subject to the RSU on 2/15/2023, and the remaining shares shall vest in twelve (12) equal quarterly installments thereafter. Awarded on May 25, 2023 pursuant to the Tandem Diabetes Care Inc. 2023 Long-Term Incentive Plan (the 2023 Plan). 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. 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. 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. /s/ Shannon M. Hansen 2025-11-19