X0508 4 2026-01-07 0001826457 Monte Rosa Therapeutics, Inc. GLUE 0001855643 Warmuth Markus MONTE ROSA THERAPEUTICS, INC. 321 HARRISON AVENUE, SUITE 900 BOSTON MA 02118 true true false false President & CEO true Common Stock 2026-01-07 4 S false 3707 23.2422 D 620696 D Common Stock 2026-01-07 4 S false 1450 23.8762 D 619246 D Common Stock 2026-01-07 4 S false 309 24.5736 D 618937 D These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on May 14, 2025. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $22.42 to $23.40, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $23.43 to $24.41, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.43 to $24.65, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. /s/ Markus Warmuth 2026-01-09