Mirum (MIRM) CEO Christopher Peetz Sells Shares, Exercises Options

What Happened

Christopher Peetz, CEO of Mirum Pharmaceuticals, exercised 20,000 stock options (fully vested) by paying $2.94 per share ($58,720 total) and, on the same day (2026-08-10), sold 20,000 common shares in open-market transactions for a combined reported proceeds of approximately $1,978,401. The sales were executed in three tranches at weighted average prices of $98.51, $99.25 and $100.14 per share. The filing notes these transactions were made pursuant to a Rule 10b5‑1 trading plan adopted March 2, 2026.

Key Details

• Transaction date: August 10, 2026; Form 4 filed Aug 11, 2026.
• Option exercise: 20,000 shares acquired at $2.94 per share (total $58,720). Footnote F5: option fully vested.
• Open-market sales (total 20,000 shares; total proceeds ≈ $1,978,401):
  • 11,683 shares at weighted avg $98.51 (range $97.93–$98.92) — F2
  • 6,017 shares at weighted avg $99.25 (range $98.94–$99.655) — F3
  • 2,300 shares at weighted avg $100.14 (range $99.995–$100.2425) — F4
• A related derivative disposition of 20,000 shares at $0 is also reported (linked to the exercise/conversion).
• Footnote F1: sales were pursuant to a Rule 10b5‑1 plan adopted March 2, 2026.
• Shares owned after the transactions are not disclosed in this filing.

Context

• This filing shows an exercise of fully vested options followed by same‑day open‑market sales of an equal number of shares. Such patterns are commonly executed under pre‑arranged 10b5‑1 plans to satisfy tax or liquidity needs; the filing itself does not state the insider’s motivation.
• Retail investors should view option exercises plus immediate sales as routine insider liquidity unless accompanied by other notable filings or disclosures.