X0306 4 2021-06-03 0 0001628171 Revolution Medicines, Inc. RVMD 0001620014 Exter Neil C/O THIRD ROCK VENTURES, LLC NEWBURY STREET, 3RD FLOOR BOSTON MA 02116 1 0 0 0 Common Stock 2021-06-03 4 S 0 0 0.00 D 0 I See footnote Common Stock 2021-06-04 4 S 0 0 0.00 D 0 I See footnote Common Stock 0 I See footnotes Common Stock 19998 D Common Stock 19998 I See footnote On June 3, 2021, Third Rock Ventures II, L.P. ("TRV II") sold 378,117 shares of Common Stock of the Issuer in multiple transactions at prices ranging from $30.00 to $30.50, inclusive, at a weighted average price per share of $30.20. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (1). After the above transaction, TRV II owned 164,996 shares of Common Stock of the Issuer. The Reporting Person is a partner of each of Third Rock Ventures GP II, L.P., TRV GP III, L.P. and Third Rock Ventures GP IV, L.P. which is the general partner of each of TRV II, Third Rock Ventures III, L.P. ("TRV III") and Third Rock Ventures IV, L.P. ("TRV IV" and collectively with TRV II and TRV III, "the Funds"), respectively. The Reporting Person disclaims beneficial ownership over the shares held by the Funds, except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that he is the beneficial owner of such shares. On June 4, 2021, TRV II sold 164,996 shares of Common Stock of the Issuer in multiple transactions at prices ranging from $30.10 to $30.76, inclusive, at a weighted average price per share of $30.23. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (4). After the above transaction, TRV II owned 0 shares of Common Stock of the Issuer. TRV III directly holds 5,524,031 shares of Common Stock of the Issuer and TRV IV directly holds 1,419,900 shares of Common Stock of the Issuer. The shares are directly held in certain estate-planning trusts over which the Reporting Person may have voting and dispositive power. The Reporting Person disclaims beneficial ownership over the shares held by such trusts except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that he is the beneficial owner of such shares. /s/ Neil Exter 2021-06-07