Magnite, Inc. Appoints New CFO and Chief Accounting Officer

What Happened

• Magnite, Inc. filed an 8‑K (dated Sept 21, 2026) reporting internal leadership appointments: Brian Gephart will become Chief Financial Officer and principal financial officer, and Haas Sullivan will become Chief Accounting Officer and principal accounting officer, both effective October 1, 2026. The appointments were announced on September 18, 2026 and disclosed via a company press release (Exhibit 99.1).
• Both executives are internal promotions: Gephart has served as Chief Accounting Officer since June 2021 and Sullivan as Vice President of Accounting since April 2020.

Key Details

• CFO equity and pay: Gephart will receive a $2.25 million equity award (70% RSUs = $1,575,000; 30% PSUs = $675,000). The RSUs will be granted on Oct 1, 2026 and vest over four years with a one‑year cliff; PSUs are expected with the 2027 annual PSU grants.
• CAO equity: Sullivan will receive RSUs valued at approximately $600,000, to be granted on Oct 1, 2026 and vest over four years with a one‑year cliff.
• Severance terms (amended for Gephart / new for Sullivan):
  • Gephart: If involuntarily terminated outside a sale, he is entitled to 12 months base salary, a pro‑rated bonus, 12 months health benefits, 12 months acceleration of time‑based vesting, and a 12‑month extension of option exercise period; if termination occurs in connection with or after a sale, he receives those benefits plus full acceleration of time‑based equity.
  • Sullivan: If involuntarily terminated outside a sale, he is entitled to 3 months base salary, a pro‑rated bonus, 3 months health benefits, 3 months vesting acceleration, and a 12‑month extension of option exercise period; if in connection with or after a sale, he is entitled to 6 months base salary, 6 months health benefits, full acceleration of time‑based equity, and a pro‑rated bonus.
• No family relationships or related‑party transactions requiring disclosure were reported for either executive.

Why It Matters

• A new CFO is a material leadership change—investors should note who will lead financial reporting and strategy going forward. Gephart brings prior CFO and accounting leadership experience, and Sullivan continues as the company’s senior accounting leader.
• The equity awards and severance arrangements may have modest impacts on future dilution and potential compensation expense; the filing discloses the grant sizes and acceleration provisions investors watch for in succession and M&A scenarios.
• Both appointments are internal promotions, which may indicate continuity in accounting and finance operations rather than an external strategic shift.