Form 4 Filing for Monte Rosa Therapeutics, Inc.

This filing details transactions made by Sharon Townson, Chief Scientific Officer of Monte Rosa Therapeutics, Inc. On June 23, 2026, Townson acquired 3,000 shares of Common Stock under a Rule 10b5-1 trading plan, with a transaction price of $6.14 per share, resulting in 70,845 shares held. Subsequently, Townson disposed of 3,000 shares of Common Stock at $20.00 per share, leaving 67,845 shares. Additionally, Townson exercised a stock option to acquire 3,000 shares of Common Stock, with the underlying shares being fully vested and exercisable. The option, with an exercise price of $6.14, was exercised as part of the same trading plan. Following these transactions, Townson holds 203,290 shares in total. The filing was signed by Phil Nickson as Attorney-in-Fact on June 25, 2026.