X0306 4 2019-08-27 0 0001438133 TANDEM DIABETES CARE INC TNDM 0001270735 ROEDER DOUGLAS A C/O DELPHI VENTURES, 63 BOVET ROAD, SUITE 351 SAN MATEO CA 94402 1 0 0 0 Common Stock 2019-08-27 4 S 0 122018 70.0969 D 1173628 I See Footnote Common Stock 2019-08-27 4 S 0 1191 70.0969 D 11460 I See Footnote Common Stock 2019-08-28 4 S 0 166704 70.4211 D 1006924 I See Footnote Common Stock 2019-08-28 4 S 0 1628 70.4211 D 9832 I See Footnote Common Stock 2019-08-28 4 S 0 16594 71.0004 D 990330 I See Footnote Common Stock 2019-08-28 4 S 0 162 71.0004 D 9670 I See Footnote This transaction was effected pursuant to a Rule 10b5-1 trading plan entered into on May 14, 2019. This transaction was executed in multiple trades at prices ranging from $70.00 to $70.65. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $70.00 to $70.99. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $71.00 to $71.03. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. The Reporting Person is a managing member of Delphi Management Partners VIII, L.L.C. ("DMP"), the general partner of Delphi Ventures VIII, L.P. As a managing member of DMP, the Reporting Person shares voting and investment power over the securities held by Delphi Ventures VIII, L.P. and may be deemed to have indirect beneficial ownership of such shares. The Reporting Person disclaims beneficial ownership of such securities held by Delphi Ventures VIII, L.P., except to the extent of his proportionate pecuniary interest therein. The Reporting Person is a managing member of Delphi Management Partners VIII, L.L.C. ("DMP"), the general partner of Delphi BioInvestments VIII, L.P. As a managing member of DMP, the Reporting Person shares voting and investment power over the securities held by Delphi BioInvestments VIII, L.P. and may be deemed to have indirect beneficial ownership of such shares. The Reporting Person disclaims beneficial ownership of such securities held by Delphi BioInvestments VIII, L.P., except to the extent of his proportionate pecuniary interest therein. /s/ Matthew T. Potter, by power of attorney for Douglass A. Roeder 2019-08-29