William John Sibold, President and CEO of Madrigal Pharmaceuticals, Inc., filed a Form 4 on September 11, 2026, reporting multiple dispositions of common stock on September 9 and September 11, 2026, pursuant to both automatic tax-withholding sales and a Rule 10b5-1 trading plan.

Key Highlights

  • Reporting person and role: William John Sibold, President and CEO and Director of Madrigal Pharmaceuticals, Inc. (NASDAQ:MDGL)
  • September 9 transactions: Fourteen separate dispositions of common stock, coded "S," with weighted average prices ranging from $527.8783 to $542.5475 per share
  • September 11 transactions: Ten separate dispositions of common stock, coded "S," with weighted average prices ranging from $533.0913 to $546.3767 per share
  • Tax-withholding sales: The September 9 sales were executed by the issuer on behalf of the reporting person to cover tax withholding obligations in connection with the vesting of restricted stock units, described as "automatic and not at the discretion of the Reporting Person"
  • 10b5-1 plan: The September 11 sales were effected automatically pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 5, 2026
  • Beneficial ownership following all reported transactions: 197,746 shares of common stock held directly

Transaction Details for Madrigal Pharmaceuticals CEO Share Dispositions

According to the filing, the September 9, 2026 transactions involved fourteen separate sales of common stock, each at a weighted average price, with individual transaction prices disclosed in ranges across footnotes. The first reported sale on that date was 131 shares at a weighted average price of $527.8783, with the issuer acting on the reporting person's behalf to satisfy tax withholding obligations tied to restricted stock unit vesting. Subsequent September 9 sales ranged from 160 shares to 1,040 shares per transaction, at weighted average prices up to $542.5475. Following all fourteen September 9 transactions, beneficial ownership stood at 202,967 shares.

The September 11, 2026 transactions consisted of ten separate sales conducted automatically under a Rule 10b5-1 trading plan that Sibold adopted on June 5, 2026, according to the filing. These transactions ranged from 60 shares at a weighted average price of $533.0913 to 1,539 shares at $544.024, with the largest single reported sale on that date being 1,539 shares. After all ten September 11 dispositions, the filing reports beneficial ownership of 197,746 shares held directly. The filing notes that all reported prices are weighted averages and that full information regarding individual transaction prices within each stated range is available upon request to the issuer, any security holder, or SEC staff.

Madrigal Pharmaceuticals is a biopharmaceutical company; its common stock is listed on NASDAQ under the symbol MDGL. The filing was signed by Mardi Dier as attorney-in-fact on September 11, 2026, and indicates the form was filed by one reporting person. The box indicating transactions made pursuant to a contract, instruction, or written plan under Rule 10b5-1(c) is checked for the filing as a whole.

What Was Disclosed

The filing discloses dispositions of Madrigal Pharmaceuticals common stock by CEO William John Sibold on September 9 and September 11, 2026, covering tax-withholding-related sales tied to RSU vesting and plan-based sales under a Rule 10b5-1 arrangement, with a final reported direct beneficial ownership of 197,746 shares.