X0609 4 2026-04-23 0 0001727196 Scholar Rock Holding Corp SRRK 0001569248 Burow Kristina false 301 BINNEY STREET CAMBRIDGE MA 02142 1 0 0 0 0 Common Stock 2026-04-23 4 M 0 7800 26.78 A 28871 D Common Stock 2026-04-23 4 M 0 28000 4.75 A 56871 D Common Stock 2026-04-23 4 M 0 36000 9.11 A 92871 D Common Stock 2026-04-23 4 M 0 18000 8.36 A 110871 D Common Stock 2345711 I See footnote Stock Option (Right to Buy) 26.78 2026-04-23 4 M 0 7800 0 D 2031-05-27 Common Stock 7800 0 D Stock Option (Right to Buy) 4.75 2026-04-23 4 M 0 28000 0 D 2032-05-26 Common Stock 28000 0 D Stock Option (Right to Buy) 9.11 2026-04-23 4 M 0 36000 0 D 2033-06-21 Common Stock 36000 0 D Stock Option (Right to Buy) 8.36 2026-04-23 4 M 0 18000 0 D 2034-06-27 Common Stock 18000 0 D Consists of 21,239 shares of common stock and 7,632 RSUs. Consists of 49,239 shares of common stock and 7,632 RSUs.. Consists of 85,239 shares of common stock and 7,632 RSUs. Consists of 103,239 shares of common stock and 7,632 RSUs. The shares are held by ARCH Venture Fund VIII, L.P. ("ARCH VIII"). ARCH Venture Partners VIII, L.P. ("GPLP"), as the sole general partner of ARCH VIII, may be deemed to beneficially own the shares held by ARCH VIII. ARCH Venture Partners VIII, LLC ("GPLLC"), as the sole general partner of GPLP, may be deemed to beneficially own the shares held by GPLP. The GPLP and GPLLC disclaim beneficial ownership of such securities, except to the extent of any pecuniary interest therein. The managing directors of the GPLLC are Keith L. Crandell, Clinton Bybee and Robert Nelsen, and they may be deemed to beneficially own the shares held by ARCH VIII. Messrs. Crandell, Bybee and Nelsen disclaim beneficial ownership of such shares, except to the extent of any pecuniary interest therein. The Reporting Person is a managing director of the GPLP. The Reporting Person owns an interest in the GPLP but does not have voting or investment control over the shares held by ARCH VIII. The Reporting Person disclaims ownership of such shares, except to the extent of her pecuniary interest therein. This stock option vested on May 26, 2022. No shares remain unvested under this stock option. This stock option vested on May 26, 2023. No shares remain unvested under this stock option. This stock option vested on June 21, 2024. No shares remain unvested under this stock option. This stock option vested on May 22, 2025. No shares remain unvested under this stock option. /s/ Junlin Ho, Attorney-in-Fact for Kristina Burow 2026-04-24