MAGNITE (MGNI) President Katie Evans Seitz Sells Shares, Exercises Options

What Happened

• Katie Evans Seitz, President, Product & Operations of MAGNITE, exercised 13,546 stock options on Sept 8, 2026 at $5.16 per share (cost ~$69,897) and separately sold a total of 43,385 shares in open-market transactions on Sept 8–9, 2026 for aggregate proceeds of about $1,023,301.
• The filing also shows the standard reporting entry for the derivative related to the exercise (13,546 options converted). These sales are typically considered routine cashing-out rather than a directional endorsement of the company.

Key Details

• Transaction dates: Sept 8, 2026 (exercise and part of sales) and Sept 9, 2026 (additional sales). Form 4 filed Sept 10, 2026 (appears timely).
• Sales: 32,285 shares at a weighted avg $23.63 (range $23.465–$23.91) and 11,100 shares at a weighted avg $23.46 (range $23.095–$24.00); total proceeds ≈ $1,023,301.
• Exercise: 13,546 options exercised at $5.16/share for ~$69,897 outlay; the derivative was converted (reported as disposed at $0.00 as part of conversion).
• Shares owned after the transactions: not specified in the provided filing.
• Notable footnotes: sales were executed under a Rule 10b5-1 trading plan adopted June 8, 2026 (F1); options were fully vested and granted as compensation (F4, F5); the filing corrects a prior reporting error about derivative holdings (F6).

Context

• For retail investors: exercises plus open-market sales are common for insiders to monetize vested compensation. The presence of a 10b5-1 plan indicates the sales were prearranged and not ad hoc trades.
• The filing is factual and does not indicate the insider’s future view of the company.