X0508 4 2023-08-16 0 0001595974 MAGNITE, INC. MGNI 0001807986 Saltz Aaron C/O MAGNITE, INC. 1250 BROADWAY, 15TH FLOOR NEW YORK NY 10001 0 1 0 0 Chief Legal Officer 0 Common Stock 2023-08-16 4 S 0 3594 8.31 D 275383 D Represents the non-discretionary sale of shares on behalf of the Reporting Person pursuant to an arrangement mandated by the Issuer to cover the tax withholding obligations associated with the vesting of restricted stock units. Reflects the transfer of 51,843 shares of the Issuer's Common Stock to the Reporting Person's ex-spouse. The Reporting Person no longer reports as beneficially owned any securities owned by the Reporting Person's ex-spouse. /s/ Aaron Saltz 2023-08-18