Hawryluk P. Kent 4

What Happened
P. Kent Hawryluk, President & CEO and a director of MBX Biosciences (MBX), exercised stock options on 2026-02-26 to acquire 28,768 shares at a $16.00 exercise price, for a total cash outlay of $460,288. The filing also reports the corresponding derivative (the option) as disposed (converted) at $0 in connection with the exercise. No shares were reported sold as part of this transaction.

Key Details

• Transaction date: 2026-02-26; Form 4 filed 2026-02-27 (timely).
• Shares acquired: 28,768 common shares at $16.00 each; total = $460,288.
• Derivative: the option underlying these shares was reported disposed/converted (code M).
• Shares owned after transaction: not specified in the provided data.
• Footnote F1: Some shares are held by the P. Kent Hawryluk Revocable Trust (he is trustee and disclaims beneficial ownership except for pecuniary interest).
• Footnote F2: Vesting: 25% of the option vested on Sept 12, 2025; remaining 75% vests in 36 equal monthly installments, contingent on continued service.

Context
This was an exercise of previously granted options (transaction code M) rather than an open-market purchase or sale. Because no sale was reported at exercise, this was not a cashless exercise—Hawryluk paid the $16 strike price to receive the shares. Exercises like this increase an insider’s raw share count but are not in themselves a direct signal of buying or selling intent.