Evans Katie Seitz 4

What Happened Katie Seitz, President, Operations of Magnite, Inc. (MGNI), had 11,204 shares forfeited on May 15, 2026 to satisfy tax withholding obligations tied to the vesting of restricted stock units. The shares were valued at $12.82 each, for a total of $143,635. This was a non-discretionary tax-withholding transaction (code F), not an open-market sale or purchase.

Key Details

• Transaction date: 2026-05-15; filing date: 2026-05-19 (timely filed).
• Price per share: $12.82; shares forfeited: 11,204; total value: $143,635.
• Transaction code: F (tax withholding / payment of tax liability). Footnote: non-discretionary forfeiture to cover tax withholding on RSU vesting.
• Shares owned after transaction: not specified in this filing.
• This is a routine withholding event and does not signal a discretionary sale.

Context This was a share-for-tax withholding related to vested RSUs (a common, administrative action). Such forfeitures are used to satisfy tax obligations and should not be interpreted as an intentional insider sale or buy signal.