X0206 3 2020-09-21 0 0001595974 MAGNITE, INC. MGNI 0001700262 Evans Katie Seitz C/O MAGNITE, INC. 12181 BLUFF CREEK DRIVE, 4TH FLOOR LOS ANGELES CA 90094 0 1 0 0 Chief Operating Officer Common Stock 520271 D Stock Option (Right to Buy) 3.96 2021-02-03 Common Stock 1442 D Stock Option (Right to Buy) 3.96 2021-06-08 Common Stock 1442 D Stock Option (Right to Buy) 4.64 2022-07-26 Common Stock 2884 D Stock Option (Right to Buy) 4.64 2022-07-19 Common Stock 2884 D Stock Option (Right to Buy) 5.46 2023-03-05 Common Stock 7212 D Stock Option (Right to Buy) 7.74 2023-07-31 Common Stock 5410 D Stock Option (Right to Buy) 3.95 2023-12-05 Common Stock 22971 D Stock Option (Right to Buy) 3.61 2028-02-27 Common Stock 56137 D Stock Option (Right to Buy) 5.16 2029-02-28 Common Stock 33546 D Stock Option (Right to Buy) 5.28 2030-04-01 Common Stock 69470 D Includes (i) 33,812 shares underlying Restricted Stock Units ("RSUs") which will vest on February 14, 2021; (ii) 13,871 shares underlying RSUs which will vest in two equal installments on each of February 14, 2021 and February 14, 2022; (iii) 37,569 shares underlying RSUs which will vest in three equal installments on each of February 14, 2021, February 14, 2022 and February 14, 2023; (iv) 92,396 shares that will vest as follows: 25,024 shares on May 15, 2021, 5,775 shares on each August 15, November 15 and February 15 thereafter until February 15, 2024, and 3,847 shares on May 15, 2024; and (v) 102,662 shares that vest in two equal installments on each of April 1, 2021 and April 1, 2022. Immediately exercisable. 25% of the total number of shares underlying this option vested on February 14, 2019 and the remaining shares vest 1/36 per month over the next 36 months thereafter, subject to continued service to the Issuer through each vesting date. 25% of the total number of shares underlying this option vested on February 14, 2020 and the remaining shares vest 1/36 per month over the next 36 months thereafter, subject to continued service to the Issuer through each vesting date. 25% of the total number of shares underlying this option will vest on April 1, 2021 and the remaining shares vest 1/36 per month over the next 36 months thereafter, subject to continued service to the Issuer through each vesting date. /s/ Aaron Saltz, Attorney-in-Fact 2020-09-25