X0508 4 2026-02-15 0001278021 MARKETAXESS HOLDINGS INC MKTX 0002021091 Fiszel Bieler Ilene C/O MARKETAXESS HOLDINGS INC. 55 HUDSON YARDS, 15TH FLOOR NEW YORK NY 10001 false true false false Chief Financial Officer false Common Stock, par value $0.003 per share 2026-02-15 4 A false 5005 0 A 9427 D Common Stock, par value $0.003 per share 2026-02-15 4 F false 439 179.36 D 8988 D Represents a grant of restricted stock units pursuant to the Company's 2020 Equity Incentive Plan. The restricted stock units shall vest 34% on February 15, 2027, 33% on February 15, 2028, and 33% on February 15, 2029. Represents the surrender of shares to the Company to satisfy the Reporting Person's tax withholding obligation upon the vesting of restricted stock units previously granted to the Reporting Person. /s/ Patrick Wilson as Attorney-in-Fact for Ilene Fiszel Bieler 2026-02-17