X0306 4 2019-05-16 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 2019-05-16 4 M 0 10000 2.59 A 12009 D Common Stock 2019-05-16 4 S 0 10000 70.45 D 2009 D Common Stock 2019-05-15 4 A 0 1256 16.93 A 3265 D Common Stock 145 I Leigh A Vosseller Trust Stock Option 2.59 2019-05-16 4 M 0 10000 0.00 D Common Stock 10000 60000 D Represents shares of common stock received upon exercise of a stock option award. The shares were sold, pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 7, 2019. The price reported is the weighted average price. The shares were sold in multiple transactions at prices ranging from $70.35 to $70.60. The Reporting Person undertakes to provide the Securities and Exchange Commission (the "SEC"), the issuer, and any security holder full information regarding the number of shares and the prices at which the shares were sold. The reporting person is voluntarily reporting the acquisition of shares of common stock pursuant to the Tandem Diabetes Care, Inc. 2013 Employee Stock Purchase Plan ("ESPP"), for the ESPP purchase period of November 16, 2018 through May 15, 2019. This transaction is also exempt under Rule 16b-3(c). The securities are held by the Leigh A. Vosseller Trust dated January 17, 2010, of which Leigh Vosseller is the Trustee. Fifty percent (50%) of the underlying shares subject to the option vested on 12/1/2018, and the remaining shares shall vest in twelve (12) equal monthly installments thereafter. The expiration date for these options is 10 years from the date of grant. David B. Berger, Attorney-in-Fact for Leigh A. Vosseller 2019-05-17