Magnite (MGNI) President Sean Buckley Sells Shares

What Happened
Sean Patrick Buckley, President, Revenue & Market Strategy at Magnite (MGNI), disposed of a total of 22,745 shares in mid‑August 2026. On 2026-08-15, 11,715 shares were forfeited by the company to cover tax withholding on vested restricted stock units (value reported $289,712). On 2026-08-17 and 2026-08-18 he sold 8,271 shares (weighted avg $24.31, proceeds $201,068) and 2,759 shares ($25.00, proceeds $68,975), respectively. Total proceeds/consideration across these transactions were approximately $559,755 (about $560K). These were sales/forfeitures (not purchases).

Key Details

• Transaction dates and prices:
  • 2026-08-15: 11,715 shares forfeited for tax withholding at $24.73 (F) — $289,712
  • 2026-08-17: 8,271 shares sold under open-market plan at weighted avg $24.31 (S) — $201,068 (prices ranged $24.05–$24.55; see F3)
  • 2026-08-18: 2,759 shares sold on-market at $25.00 (S) — $68,975
• Shares disposed total: 22,745 shares; total proceeds ≈ $559,755.
• Shares owned after transaction: Not disclosed in the filing.
• Notable footnotes:
  • F1: 11,715 shares were non‑discretionarily forfeited to satisfy tax withholding for RSU vesting.
  • F2: The open‑market sales were effected under a Rule 10b5‑1 trading plan adopted 9/10/2025.
  • F3: The 8,271‑share sale was executed in multiple trades at prices between $24.05 and $24.55; $24.31 is the weighted avg.
• Filing: Form 4 filed 2026-08-18 reporting transactions through 2026-08-15.

Context
The 11,715‑share transaction was a routine tax‑withholding related to RSU vesting (a common, non‑discretionary mécanism). The subsequent open‑market sales were carried out under a pre‑existing 10b5‑1 plan, which typically indicates scheduled sales rather than opportunistic trades. Sales and forfeitures do not necessarily indicate a change in the insider’s view of the company; purchases tend to be more instructive about positive insider sentiment.