Director Kevin Bitterman filed a Form 4 with the SEC on September 15, 2026, reporting the exercise of three stock option grants and the sale of all resulting common shares of Disc Medicine, Inc. (NASDAQ:IRON) on September 11, 2026.

Key Highlights

  • Options exercised: Bitterman exercised three fully vested stock options covering 7,136 shares at $45.69, 10,000 shares at $38.85, and 10,000 shares at $50.86, for a combined 27,136 shares acquired.
  • Shares sold: All 27,136 resulting common shares were sold on September 11, 2026, at a weighted average price of $70.11, with individual transaction prices ranging from $70.10 to $70.37.
  • Direct ownership after transactions: Following the reported transactions, Bitterman holds 0 shares of common stock directly.
  • Indirect holdings remain: Bitterman retains indirect interests in 318,866 shares held by Atlas Venture Opportunity Fund I, L.P., 312,230 shares held by Atlas Venture Opportunity Fund II, L.P., and 13,427 shares held by Atlas Venture Fund XII, L.P.
  • Beneficial ownership disclaimed: According to the filing, Bitterman disclaims beneficial ownership of all indirectly held shares except to the extent of his pecuniary interest in each fund.

Kevin Bitterman's Option Exercises and Share Sales at Disc Medicine

According to the filing, Kevin Bitterman, identified as a director of Disc Medicine, Inc., exercised three separate stock option grants on September 11, 2026. The first covered 7,136 shares at an exercise price of $45.69, with an expiration date of June 8, 2033. The second covered 10,000 shares at $38.85, expiring June 11, 2034. The third covered 10,000 shares at $50.86, expiring June 10, 2035. The filing notes all three options were "fully vested and exercisable" at the time of exercise.

On the same date, the filing reports that Bitterman sold all 27,136 shares acquired through those exercises. The sale price is reported as a weighted average of $70.11 per share, with individual transactions occurring at prices between $70.10 and $70.37. The filing states that Bitterman will provide full per-price transaction detail to the issuer, any security holder, or SEC staff upon request. After these transactions, his directly held position in Disc Medicine common stock is reported as zero.

The filing also discloses three indirect ownership positions. A total of 318,866 shares are held by Atlas Venture Opportunity Fund I, L.P.; 312,230 shares by Atlas Venture Opportunity Fund II, L.P.; and 13,427 shares by Atlas Venture Fund XII, L.P. In each case, Bitterman is described as a member of the respective general partner entity. The filing states he disclaims beneficial ownership of those shares except to the extent of any pecuniary interest he may hold.

What Was Disclosed

Disc Medicine director Kevin Bitterman reported the exercise of three fully vested stock options totaling 27,136 shares and the same-day sale of all resulting shares on September 11, 2026, leaving him with zero directly held common shares.