Who owns MarketAxess Holdings (MKTX)
Which tracked institutional funds hold MKTX, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See MKTX company fundamentals →
Ownership as of the 2026-Q2 13F filings (latest filed 2026-09-22). 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
Conviction spread
MKTX’s largest tracked holder by dollar value, BlackRock, Inc., sizes it at 0.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.0pp gap the other way — the median holder sizes MKTX more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in MKTX divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2026-Q1 and 2026-Q2, we do not read how tracked institutions changed their MKTX positions: many holders could not be matched across the two filings, most often because the security’s identifier changed and our mapping is incomplete, or because funds are still filing for the newer quarter. Over the same quarter, open-market insider Form 4s were net sales.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Institutional holders
One row per tracked fund, most shares held first (every row is from one quarter; reported value breaks ties). “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding.
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| BlackRock, Inc. added | 3,999,836 | $454M | 10.8% | 2026-Q2 |
| PRIMECAP MANAGEMENT CO/CA/ added | 3,504,905 | $398M | 9.5% | 2026-Q2 |
| North Reef Capital Management LP added | 3,395,000 | $385M | 9.2% | 2026-Q2 |
| VANGUARD PORTFOLIO MANAGEMENT LLC trimmed | 2,100,273 | $238M | 5.7% | 2026-Q2 |
| AQR CAPITAL MANAGEMENT LLC trimmed | 1,987,288 | $223M | 5.3% | 2026-Q2 |
| VANGUARD CAPITAL MANAGEMENT LLC trimmed | 1,546,670 | $176M | 4.2% | 2026-Q2 |
| FMR LLC trimmed | 1,404,998 | $159M | 3.8% | 2026-Q2 |
| STATE STREET CORP added | 1,281,769 | $145M | 3.5% | 2026-Q2 |
| NEUBERGER BERMAN GROUP LLC added | 1,229,929 | $140M | 3.3% | 2026-Q2 |
| GOLDMAN SACHS GROUP INC added | 1,031,309 | $117M | 2.8% | 2026-Q2 |
| BANK OF MONTREAL /CAN/ trimmed | 1,017,024 | $115M | 2.7% | 2026-Q2 |
| GEODE CAPITAL MANAGEMENT, LLC added | 994,772 | $113M | 2.7% | 2026-Q2 |
| VAN ECK ASSOCIATES CORP trimmed | 924,617 | $105M | 2.5% | 2026-Q2 |
| DIMENSIONAL FUND ADVISORS LP added | 597,894 | $68M | 1.6% | 2026-Q2 |
| NORGES BANK added | 572,422 | $65M | 1.5% | 2026-Q2 |
| TWO SIGMA INVESTMENTS, LP added | 543,890 | $62M | 1.5% | 2026-Q2 |
| GUARDCAP ASSET MANAGEMENT Ltd trimmed | 536,324 | $62M | 1.5% | 2026-Q2 |
| Azora Capital LP added | 513,081 | $58M | 1.4% | 2026-Q2 |
| Davis Asset Management, L.P. added | 500,000 | $57M | 1.3% | 2026-Q2 |
| CITADEL ADVISORS LLC added | 481,689 | $55M | 1.3% | 2026-Q2 |
| JPMORGAN CHASE & CO added | 438,001 | $48M | 1.1% | 2026-Q2 |
| MORGAN STANLEY trimmed | 422,864 | $48M | 1.1% | 2026-Q2 |
| LOS ANGELES CAPITAL MANAGEMENT LLC added | 392,065 | $44M | 1.1% | 2026-Q2 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 330,815 | $38M | 0.9% | 2026-Q2 |
| BANK OF AMERICA CORP /DE/ added | 303,517 | $34M | 0.8% | 2026-Q2 |
| UBS Group AG added | 278,745 | $32M | 0.8% | 2026-Q2 |
| Bank of New York Mellon Corp trimmed | 257,642 | $29M | 0.7% | 2026-Q2 |
| RDST Capital LLC trimmed | 247,112 | $28M | 0.7% | 2026-Q2 |
| NORTHERN TRUST CORP added | 246,521 | $28M | 0.7% | 2026-Q2 |
| COOKE & BIELER LP added | 238,755 | $27M | 0.6% | 2026-Q2 |
| VANGUARD FIDUCIARY TRUST CO trimmed | 223,656 | $25M | 0.6% | 2026-Q2 |
| BNP PARIBAS ASSET MANAGEMENT Holding S.A. added | 204,309 | $23M | 0.6% | 2026-Q2 |
| VICTORY CAPITAL MANAGEMENT INC trimmed | 202,731 | $23M | 0.5% | 2026-Q2 |
| RENAISSANCE TECHNOLOGIES LLC added | 200,000 | $23M | 0.5% | 2026-Q2 |
| Connor, Clark & Lunn Investment Management Ltd. added | 186,658 | $21M | 0.5% | 2026-Q2 |
| PRINCIPAL FINANCIAL GROUP INC trimmed | 173,312 | $20M | 0.5% | 2026-Q2 |
| Freestone Grove Partners LP added | 172,799 | $20M | 0.5% | 2026-Q2 |
| Public Sector Pension Investment Board trimmed | 157,338 | $18M | 0.4% | 2026-Q2 |
| Sone Capital Management, LLC trimmed | 155,522 | $18M | 0.4% | 2026-Q2 |
| Nuveen, LLC added | 148,468 | $17M | 0.4% | 2026-Q2 |
| Invesco Ltd. added | 140,817 | $16M | 0.4% | 2026-Q2 |
| TUDOR INVESTMENT CORP ET AL added | 137,847 | $16M | 0.4% | 2026-Q2 |
| Champlain Investment Partners, LLC trimmed | 136,087 | $15M | 0.4% | 2026-Q2 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP trimmed | 122,005 | $14M | 0.3% | 2026-Q2 |
| M&G PLC new | 121,309 | $14M | 0.3% | 2026-Q2 |
| BANK OF NOVA SCOTIA added | 115,410 | $13M | 0.3% | 2026-Q2 |
| CIBC Bancorp USA Inc. added | 114,968 | $13M | 0.3% | 2026-Q2 |
| RAYMOND JAMES FINANCIAL INC trimmed | 114,278 | $13M | 0.3% | 2026-Q2 |
| ALGERT GLOBAL LLC added | 112,400 | $13M | 0.3% | 2026-Q2 |
| MILLENNIUM MANAGEMENT LLC trimmed | 109,590 | $12M | 0.3% | 2026-Q2 |
| HEARTLAND ADVISORS INC added | 104,926 | $12M | 0.3% | 2026-Q2 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC trimmed | 104,853 | $12M | 0.3% | 2026-Q2 |
| Walleye Capital LLC trimmed | 94,002 | $11M | 0.3% | 2026-Q2 |
| HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND trimmed | 92,100 | $10M | 0.2% | 2026-Q2 |
| Invenomic Capital Management LP new | 90,441 | $10M | 0.2% | 2026-Q2 |
| Legal & General Group Plc trimmed | 84,460 | $10M | 0.2% | 2026-Q2 |
| AMERIPRISE FINANCIAL INC added | 79,372 | $9M | 0.2% | 2026-Q2 |
| Jump Financial, LLC added | 78,566 | $9M | 0.2% | 2026-Q2 |
| CIBC WORLD MARKET INC. added | 78,286 | $9M | 0.2% | 2026-Q2 |
| JANE STREET GROUP, LLC added | 77,353 | $9M | 0.2% | 2026-Q2 |
| FLOSSBACH VON STORCH SE trimmed | 75,000 | $9M | 0.2% | 2026-Q2 |
| RHUMBLINE ADVISERS trimmed | 72,725 | $8M | 0.2% | 2026-Q2 |
| Swiss National Bank trimmed | 71,400 | $8M | 0.2% | 2026-Q2 |
| Trexquant Investment LP trimmed | 66,681 | $8M | 0.2% | 2026-Q2 |
| CITIGROUP INC added | 64,762 | $7M | 0.2% | 2026-Q2 |
| Alpha Omega Wealth Management LLC added | 61,453 | $7M | 0.2% | 2026-Q2 |
| STIFEL FINANCIAL CORP added | 56,622 | $6M | 0.2% | 2026-Q2 |
| SEI INVESTMENTS CO added | 56,022 | $6M | 0.2% | 2026-Q2 |
| Y-Intercept (Hong Kong) Ltd added | 54,792 | $6M | 0.1% | 2026-Q2 |
| VAN DEN BERG MANAGEMENT I, INC added | 52,054 | $6M | 0.1% | 2026-Q2 |
| Brevan Howard Capital Management LP added | 51,050 | $6M | 0.1% | 2026-Q2 |
| STATE OF WISCONSIN INVESTMENT BOARD added | 51,004 | $6M | 0.1% | 2026-Q2 |
| California Public Employees Retirement System trimmed | 49,950 | $6M | 0.1% | 2026-Q2 |
| First Eagle Investment Management, LLC added | 49,577 | $6M | 0.1% | 2026-Q2 |
| D. E. Shaw & Co., Inc. added | 47,977 | $5M | 0.1% | 2026-Q2 |
| Quantinno Capital Management LP added | 47,575 | $5M | 0.1% | 2026-Q2 |
| FIRST TRUST ADVISORS LP added | 46,658 | $5M | 0.1% | 2026-Q2 |
| WILSON ASSET MANAGEMENT (INTERNATIONAL) PTY LTD added | 45,042 | $5M | 0.1% | 2026-Q2 |
| Mariner, LLC trimmed | 44,790 | $5M | 0.1% | 2026-Q2 |
| Cerity Partners LLC trimmed | 44,382 | $5M | 0.1% | 2026-Q2 |
| AMERICAN CENTURY COMPANIES INC added | 44,363 | $5M | 0.1% | 2026-Q2 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM trimmed | 42,443 | $5M | 0.1% | 2026-Q2 |
| DF DENT & CO INC trimmed | 39,303 | $4M | 0.1% | 2026-Q2 |
| ROYAL BANK OF CANADA added | 39,121 | $4M | 0.1% | 2026-Q2 |
| MARSHALL WACE, LLP trimmed | 39,090 | $4M | 0.1% | 2026-Q2 |
| Corebridge Financial, Inc. added | 38,650 | $4M | 0.1% | 2026-Q2 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 38,521 | $4M | 0.1% | 2026-Q2 |
| Holocene Advisors, LP trimmed | 38,269 | $4M | 0.1% | 2026-Q2 |
| Prana Capital Management, LP added | 37,877 | $4M | 0.1% | 2026-Q2 |
| FJ Capital Management LLC added | 37,237 | $4M | 0.1% | 2026-Q2 |
| Taylor Hoffman Capital Management LLC added | 35,895 | $4M | 0.1% | 2026-Q2 |
| BNP PARIBAS FINANCIAL MARKETS trimmed | 35,288 | $4M | 0.1% | 2026-Q2 |
| STATE BOARD OF ADMINISTRATION OF FLORIDA RETIREMENT SYSTEM trimmed | 34,407 | $4M | 0.1% | 2026-Q2 |
| READYSTATE ASSET MANAGEMENT LP added | 33,794 | $4M | 0.1% | 2026-Q2 |
| HSBC HOLDINGS PLC added | 33,576 | $4M | 0.1% | 2026-Q2 |
| VANGUARD ASSET MANAGEMENT, Ltd added | 33,563 | $4M | 0.1% | 2026-Q2 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 32,579 | $4M | 0.1% | 2026-Q2 |
| Squarepoint Ops LLC added | 32,462 | $4M | 0.1% | 2026-Q2 |
| PRUDENTIAL FINANCIAL INC trimmed | 32,341 | $4M | 0.1% | 2026-Q2 |
| Elo Mutual Pension Insurance Co added | 31,860 | $4M | 0.1% | 2026-Q2 |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.