X0306 4 2018-05-29 0 0001727196 Scholar Rock Holding Corp SRRK 0001740152 BUCKLER ALAN J. C/O SCHOLAR ROCK HOLDING CORPORATION 620 MEMORIAL DRIVE, 2ND FLOOR CAMBRIDGE MA 02139 0 1 0 0 Chief Scientific Officer Stock Option (Right to Buy) 14 2018-05-29 4 A 0 15838 0 A 2028-05-23 Common Stock` 15838 15838 D This option was granted on May 23, 2018 and following the closing of the Issuer's initial public offering on May 29, 2018, the vesting period for the stock option commenced and the stock option shall vest and become exercisable in 16 equal quarterly installments with the first quarterly amount to vest on August 29, 2018. /s/ Junlin Ho, Attorney-in-Fact for Alan J. Buckler 2018-05-31