X0306 4 2018-11-15 0 0001438133 TANDEM DIABETES CARE INC TNDM 0001726322 Vosseller Leigh C/O TANDEM DIABETES CARE, INC. 11075 ROSELLE STREET SAN DIEGO CA 92121 0 1 0 0 EVP and CFO Common Stock 2018-11-15 4 A 0 1255 16.92 A 2145 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 June 15, 2018 through November 15, 2018. This transaction is also exempt under Rule 16b-3(c). In accordance with the ESPP, these shares were purchased based on 85% of the closing price of the issuer's common stock on June 15, 2018. David B. Berger, Attorney-in-Fact for Leigh A. Vosseller 2018-11-19