INSMED Director David R. Brennan Sells $3.1M in Common Stock

Transaction Overview

On September 11, 2026, INSMED Inc ($INSM) filed a Form 4 disclosing that Director David R. Brennan sold 25,000 shares of Common Stock on September 9, 2026, at an execution price of $124.00 per share, resulting in a total transaction value of $3,100,000.00.

Position & Ownership Context

• Transaction Code: S (Open market or private sale)
• Pre-Transaction Direct Holding: 64,238 shares
• Post-Transaction Direct Holding: 39,238 shares (a direct holding reduction of ~38.9%)
• Indirect Holdings: 60,000 shares held indirectly via a spouse revocable trust
• 10b5-1 Plan Indicator: 0 (Not marked as executed under a Rule 10b5-1 trading plan)

Key Takeaways

• Material Disposition: A $3.1M open-market sale by a board director represents notable insider profit-taking.
• Retained Exposure: Despite the reduction in directly held shares, Mr. Brennan maintains a total economic interest in 99,238 shares across direct and indirect holdings.