X0609 4 2026-06-01 0001595974 MAGNITE, INC. MGNI 0001966857 Buonasera David false C/O MAGNITE, INC. 1250 BROADWAY, 9TH FLOOR NEW YORK NY 10001 false true false false CHIEF TECHNOLOGY OFFICER 1 Common Stock 2026-06-01 4 S 0 1409 15 D 292784 D The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on September 11, 2025. /s/ Aaron Saltz, attorney-in-fact 2026-06-03