X0306 4 2019-02-19 0 0001278021 MARKETAXESS HOLDINGS INC MKTX 0001249885 DELISE ANTONIO L C/O MARKETAXESS HOLDINGS, INC. 299 PARK AVENUE NEW YORK NY 10171 0 1 0 0 Chief Financial Officer Common Stock, par value $0.003 per share 2019-02-19 4 S 0 8000 231.9906 D 36901 D Common Stock, par value $0.003 per share 2019-02-21 4 A 0 7356 0.00 A 44257 D The transactions were executed in multiple trades at prices ranging from $231.67 to $232.11. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer. Settlement of performance shares granted January 22, 2016 pursuant to the Company's 2012 Incentive Plan, which were settled based on the achievement by the Issuer of adjusted pre-tax operating income targets during the performance period and are payable in shares of restricted stock. The shares of restricted stock will vest in two equal installments on January 31, 2020 and January 31, 2021. Exhibit 24 - Power of Attorney /s/ Scott Pintoff, as Attorney-in-Fact for Antonio L. Delise 2019-02-21