X0306 4 2020-05-08 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 2020-05-08 4 M 0 1133 88.25 A 952077 D Common Stock, par value $0.003 per share 2020-05-08 4 M 0 58000 88.25 A 1010077 D Common Stock, par value $0.003 per share 2020-05-08 4 F 0 21169 484.32 D 988908 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 500 476.72 D 988408 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 1430 477.39 D 986978 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 800 478.52 D 986178 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 2000 479.64 D 984178 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 1000 480.62 D 983178 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 2200 481.78 D 980978 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 3302 482.76 D 977676 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 4542 483.82 D 973134 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 3199 484.62 D 969935 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 300 485.79 D 969635 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 1498 487.26 D 968137 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 1701 488.40 D 966436 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 824 489.26 D 965612 D Common Stock, par value $0.003 per share 2020-05-08 4 S 0 1704 490.22 D 963908 D Common Stock, par value $0.003 per share 2000 I By Immediate Family Members Stock Option (right to buy) 88.25 2020-05-08 4 M 0 1133 0.00 D 2020-07-15 Common Stock 1133 0 D Stock Option (right to buy) 88.25 2020-05-08 4 M 0 58000 0.00 D 2020-07-15 Common Stock 58000 58582 D The Reporting Person has elected to exercise and hold the shares at this time. This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. The transactions were executed in multiple trades at prices ranging from $476.00 to $476.99. 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. The transactions were executed in multiple trades at prices ranging from $477.00 to $477.88. 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. The transactions were executed in multiple trades at prices ranging from $478.10 to $478.90. 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. The transactions were executed in multiple trades at prices ranging from $479.14 to $480.12. 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. The transactions were executed in multiple trades at prices ranging from $480.16 to $481.05. 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. The transactions were executed in multiple trades at prices ranging from $481.17 to $482.13. 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. The transactions were executed in multiple trades at prices ranging from $482.30 to $483.27. 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. The transactions were executed in multiple trades at prices ranging from $483.30 to $484.24. 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. The transactions were executed in multiple trades at prices ranging from $484.31 to $485.22. 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. The transactions were executed in multiple trades at prices ranging from $485.41 to $486.14. 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. The transactions were executed in multiple trades at prices ranging from $486.72 to $487.65. 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. The transactions were executed in multiple trades at prices ranging from $487.85 to $488.81. 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. The transactions were executed in multiple trades at prices ranging from $488.87 to $489.83. 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. The transactions were executed in multiple trades at prices ranging from $489.92 to $490.81. 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. The stock options were fully exercisable. /s/ Jason Edelstein, as Attorney-in-Fact for Richard M. McVey 2020-05-12