X0306 4 2018-02-09 0 0001438133 TANDEM DIABETES CARE INC TNDM 0001582779 Allen Dick C/O TANDEM DIABETES CARE, INC., 11045 ROSELLE STREET SAN DIEGO CA 92121 1 0 0 0 Common Stock 2018-02-09 4 P 0 50000 2.00 A 63160 I See footnotes Common Stock 2018-02-09 4 P 0 10000 2.00 A 13898 I See footnotes The amount of securities beneficially owned following the reported transactions reflects the 10 for 1 reverse stock split of the Issuer's issued and outstanding common stock which was effective on October 9, 2017. The securities are held by the Allen Family Trust dated October 12, 1981. The securities are held by Allen Cornerstone Ventures L.P. The Reporting Person is the managing partner of Allen Cornerstone Ventures L.P. and may be deemed to have indirect beneficial ownership of such securities. The Reporting Person disclaims beneficial ownership of such securities held by Allen Cornerstone Ventures L.P., except to the extent of his proportionate pecuniary interest therein. /s/ David B. Berger, Attorney-in-Fact for Dick P. Allen 2018-02-13