X0306 4 2023-01-18 0 0001278021 MARKETAXESS HOLDINGS INC MKTX 0001296466 McVey Richard M C/O MARKETAXESS HOLDINGS INC. 55 HUDSON YARDS, 15TH FLOOR NEW YORK NY 10001 1 1 0 0 Chairman & CEO Common Stock, par value $0.003 per share 2023-01-18 4 A 0 4589 0.00 A 661934 D Common Stock, par value $0.003 per share 2000 I By Immediate Family Members On January 18, 2023, the Compensation and Talent Committee of the Board of Directors of the Issuer certified the performance metrics relating to the performance stock units granted to the Reporting Person on January 15, 2020. The performance stock units continue to be subject to a service condition that will be satisfied on January 31, 2023. /s/ Jason Edelstein, as Attorney-in-Fact for Richard M. McVey 2023-01-20