| Name | Relationship | Address | Signature | Signature date | CIK |
|---|---|---|---|---|---|
| Casper Stephen P | Director | C/O MARKETAXESS HOLDINGS INC., 55 HUDSON YARDS, 15TH FLOOR, NEW YORK | /s/ Patrick Wilson, as Attorney-in-Fact for Stephen Casper | 09 Sep 2025 | 0001296969 |
| Type | Sym | Class | Transaction | Value $ | Shares | Change % | * Price $ | Shares After | Date | Ownership | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| transaction | MKTX | Common Stock, par value $0.003 per share | Sale | $298,544 | -1,600 | -3.6% | $186.59 | 43,208 | 08 Sep 2025 | By family trust | |
| holding | MKTX | Common Stock, par value $0.003 per share | 9,985 | 08 Sep 2025 | Direct |