MarketAxess Holdings Inc. (MKTX) ownership: Top institutional holder: VANGUARD GROUP INC ($695.98M). Insider activity: Net Seller (1 buys, 19 sells). 10 recent congressional STOCK Act disclosures. SEC EDGAR first-party data.
| Holder | Shares | Market Value | Reported |
|---|---|---|---|
| VANGUARD GROUP INC | 3839889.00 | $695.98M | 2025-12-31 |
| BlackRock, Inc. | 4075154.00 | $672.32M | 2026-03-31 |
| PRIMECAP MANAGEMENT CO/CA/ | 3347125.00 | $552.21M | 2026-03-31 |
| AQR CAPITAL MANAGEMENT LLC | 2683745.00 | $442.76M | 2026-03-31 |
| VANGUARD PORTFOLIO MANAGEMENT LLC | 2163671.00 | $356.96M | 2026-03-31 |
| North Reef Capital Management LP | 1875000.00 | $309.34M | 2026-03-31 |
| VANGUARD CAPITAL MANAGEMENT LLC | 1609259.00 | $265.50M | 2026-03-31 |
| FMR LLC | 1519421.00 | $250.67M | 2026-03-31 |
| Insider | Transaction | Value | Date |
|---|---|---|---|
| Sell | null | 2026-06-18 | |
| Sell | null | 2026-06-10 | |
| Sell | null | 2026-06-10 | |
| Sell | null | 2026-06-10 | |
| Sell | null | 2026-06-10 | |
| Sell | null | 2026-06-10 | |
| Sell | null | 2026-06-10 | |
| Sell | null | 2026-06-10 |
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Institutional data from SEC Form 13F. Insider data from SEC Form 4. Congressional data from STOCK Act disclosures. Not personalized investment advice.