Who owns MKTX (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-Q1 13F filings. 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
83 tracked funds added or opened MKTX while 141 trimmed or exited it between 2025-Q4 and 2026-Q1 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
MKTX’s largest tracked holder by dollar value, VANGUARD GROUP 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 2025-Q4 and 2026-Q1, across 446 tracked filers holding MKTX, 239 increased or opened the position and 250 reduced or closed it; over the same quarter, open-market insider Form 4 buying and selling roughly offset.
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
Funds opening or closing a position in MKTX between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 29
- VANGUARD PORTFOLIO MANAGEMENT LLC$357M
- VANGUARD CAPITAL MANAGEMENT LLC$265M
- Point72 Asset Management, L.P.$42M
- Driehaus Capital Management LLC$39M
- VANGUARD FIDUCIARY TRUST CO$38M
- EUBEL BRADY & SUTTMAN ASSET MANAGEMENT INC$18M
Full exits 37
- VANGUARD GROUP INC$686M
- TWO SIGMA ADVISERS, LP$31M
- Gillson Capital LP$15M
- VOLORIDGE INVESTMENT MANAGEMENT, LLC$15M
- BW Gestao de Investimentos Ltda.$9M
- Quadrature Capital Ltd$7M
Largest adds
- MILLENNIUM MANAGEMENT LLC$125M
- NEUBERGER BERMAN GROUP LLC$60M
- GOLDMAN SACHS GROUP INC$53M
- Amundi$37M
- UBS Group AG$26M
- Sone Capital Management, LLC$25M
Largest trims
- FMR LLC$114M
- GUARDCAP ASSET MANAGEMENT Ltd$103M
- CITADEL ADVISORS LLC$100M
- BlackRock, Inc.$48M
- Holocene Advisors, LP$32M
- JPMORGAN CHASE & CO$28M
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| BlackRock, Inc. added | 3,825,134 | $631M | 8.8% | 2026-Q1 |
| PRIMECAP MANAGEMENT CO/CA/ added | 3,347,125 | $552M | 7.7% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 2,683,411 | $443M | 6.2% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 2,163,671 | $357M | 5.0% | 2026-Q1 |
| North Reef Capital Management LP added | 1,875,000 | $309M | 4.3% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 1,609,259 | $265M | 3.7% | 2026-Q1 |
| FMR LLC trimmed | 1,511,419 | $249M | 3.5% | 2026-Q1 |
| STATE STREET CORP added | 1,280,857 | $211M | 2.9% | 2026-Q1 |
| VAN ECK ASSOCIATES CORP added | 1,239,285 | $204M | 2.8% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 1,087,188 | $179M | 2.5% | 2026-Q1 |
| BANK OF MONTREAL /CAN/ added | 1,020,559 | $168M | 2.3% | 2026-Q1 |
| NEUBERGER BERMAN GROUP LLC added | 966,029 | $159M | 2.2% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 862,987 | $142M | 2.0% | 2026-Q1 |
| NORGES BANK added | 507,346 | $110M | 1.5% | 2026-Q1 |
| GUARDCAP ASSET MANAGEMENT Ltd trimmed | 643,370 | $106M | 1.5% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 581,484 | $96M | 1.3% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP trimmed | 524,024 | $86M | 1.2% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 509,043 | $84M | 1.2% | 2026-Q1 |
| MORGAN STANLEY added | 490,537 | $81M | 1.1% | 2026-Q1 |
| Findlay Park Partners LLP trimmed | 480,600 | $79M | 1.1% | 2026-Q1 |
| JPMORGAN CHASE & CO trimmed | 432,826 | $71M | 1.0% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 338,507 | $56M | 0.8% | 2026-Q1 |
| Walleye Capital LLC added | 332,723 | $55M | 0.8% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS trimmed | 319,302 | $53M | 0.7% | 2026-Q1 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP added | 295,470 | $49M | 0.7% | 2026-Q1 |
| RDST Capital LLC trimmed | 295,267 | $49M | 0.7% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 289,940 | $48M | 0.7% | 2026-Q1 |
| UBS Group AG added | 272,238 | $45M | 0.6% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 263,858 | $44M | 0.6% | 2026-Q1 |
| Amundi added | 258,708 | $43M | 0.6% | 2026-Q1 |
| Point72 Asset Management, L.P. added | 252,825 | $42M | 0.6% | 2026-Q1 |
| Driehaus Capital Management LLC added | 239,256 | $39M | 0.5% | 2026-Q1 |
| NORTHERN TRUST CORP added | 236,350 | $39M | 0.5% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 229,427 | $38M | 0.5% | 2026-Q1 |
| COOKE & BIELER LP added | 226,220 | $37M | 0.5% | 2026-Q1 |
| Champlain Investment Partners, LLC added | 210,076 | $35M | 0.5% | 2026-Q1 |
| VICTORY CAPITAL MANAGEMENT INC added | 204,932 | $34M | 0.5% | 2026-Q1 |
| BNP PARIBAS ASSET MANAGEMENT Holding S.A. added | 203,425 | $34M | 0.5% | 2026-Q1 |
| Public Sector Pension Investment Board added | 192,230 | $32M | 0.4% | 2026-Q1 |
| PRINCIPAL FINANCIAL GROUP INC added | 181,798 | $30M | 0.4% | 2026-Q1 |
| Connor, Clark & Lunn Investment Management Ltd. added | 174,059 | $29M | 0.4% | 2026-Q1 |
| IEQ CAPITAL, LLC trimmed | 173,891 | $29M | 0.4% | 2026-Q1 |
| JANUS HENDERSON GROUP PLC added | 168,797 | $28M | 0.4% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC trimmed | 167,100 | $28M | 0.4% | 2026-Q1 |
| Sone Capital Management, LLC added | 159,966 | $26M | 0.4% | 2026-Q1 |
| Nuveen, LLC added | 148,081 | $24M | 0.3% | 2026-Q1 |
| HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND added | 145,628 | $24M | 0.3% | 2026-Q1 |
| HRT FINANCIAL LP trimmed | 136,952 | $23M | 0.3% | 2026-Q1 |
| RAYMOND JAMES FINANCIAL INC added | 121,635 | $20M | 0.3% | 2026-Q1 |
| EUBEL BRADY & SUTTMAN ASSET MANAGEMENT INC new | 111,483 | $18M | 0.3% | 2026-Q1 |
| Davis Asset Management, L.P. new | 108,846 | $18M | 0.3% | 2026-Q1 |
| FLOSSBACH VON STORCH SE added | 108,100 | $18M | 0.2% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC trimmed | 107,110 | $18M | 0.2% | 2026-Q1 |
| Assenagon Asset Management S.A. added | 104,801 | $17M | 0.2% | 2026-Q1 |
| Polar Asset Management Partners Inc. added | 104,174 | $17M | 0.2% | 2026-Q1 |
| Legal & General Group Plc trimmed | 90,720 | $15M | 0.2% | 2026-Q1 |
| RHUMBLINE ADVISERS added | 89,961 | $15M | 0.2% | 2026-Q1 |
| Invesco Ltd. trimmed | 87,134 | $14M | 0.2% | 2026-Q1 |
| Cerity Partners LLC added | 84,001 | $14M | 0.2% | 2026-Q1 |
| Goodman Financial Corp added | 83,163 | $14M | 0.2% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 82,159 | $14M | 0.2% | 2026-Q1 |
| Mariner, LLC added | 79,144 | $13M | 0.2% | 2026-Q1 |
| CWM, LLC trimmed | 73,978 | $12M | 0.2% | 2026-Q1 |
| Swiss National Bank | 73,700 | $12M | 0.2% | 2026-Q1 |
| California Public Employees Retirement System trimmed | 72,522 | $12M | 0.2% | 2026-Q1 |
| Trexquant Investment LP added | 70,378 | $12M | 0.2% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC trimmed | 69,885 | $12M | 0.2% | 2026-Q1 |
| Gotham Asset Management, LLC added | 60,213 | $10M | 0.1% | 2026-Q1 |
| HEARTLAND ADVISORS INC added | 58,334 | $10M | 0.1% | 2026-Q1 |
| WEALTH ENHANCEMENT ADVISORY SERVICES, LLC added | 56,172 | $9M | 0.1% | 2026-Q1 |
| ICICI Prudential Asset Management Co Ltd | 49,289 | $8M | 0.1% | 2026-Q1 |
| Quantinno Capital Management LP added | 46,990 | $8M | 0.1% | 2026-Q1 |
| ALLIANCEBERNSTEIN L.P. added | 41,259 | $7M | 0.1% | 2026-Q1 |
| T. Rowe Price Investment Management, Inc. trimmed | 44,278 | $7M | 0.1% | 2026-Q1 |
| Holocene Advisors, LP trimmed | 43,799 | $7M | 0.1% | 2026-Q1 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM added | 43,688 | $7M | 0.1% | 2026-Q1 |
| Schonfeld Strategic Advisors LLC trimmed | 42,596 | $7M | 0.1% | 2026-Q1 |
| VANGUARD GROUP INC trimmed | 3,783,809 | $686M | 9.5% | 2025-Q4 stale |
| Burgundy Asset Management Ltd. added | 692,216 | $127M | 1.8% | 2025-Q3 stale |
| MARSHALL WACE, LLP trimmed | 358,332 | $78M | 1.1% | 2025-Q1 stale |
| CONGRESS ASSET MANAGEMENT CO trimmed | 286,276 | $64M | 0.9% | 2025-Q2 stale |
| TWO SIGMA ADVISERS, LP trimmed | 171,600 | $31M | 0.4% | 2025-Q4 stale |
| Cubist Systematic Strategies, LLC added | 152,726 | $27M | 0.4% | 2025-Q3 stale |
| Savant Capital, LLC added | 116,266 | $26M | 0.4% | 2025-Q2 stale |
| WESTWOOD HOLDINGS GROUP INC trimmed | 83,495 | $19M | 0.3% | 2025-Q2 stale |
| SCHRODER INVESTMENT MANAGEMENT GROUP trimmed | 83,019 | $19M | 0.3% | 2025-Q2 stale |
| Kodai Capital Management LP trimmed | 77,944 | $17M | 0.2% | 2025-Q1 stale |
| Gillson Capital LP added | 80,563 | $15M | 0.2% | 2025-Q4 stale |
| VOLORIDGE INVESTMENT MANAGEMENT, LLC trimmed | 80,135 | $15M | 0.2% | 2025-Q4 stale |
| Freestone Grove Partners LP added | 75,388 | $13M | 0.2% | 2025-Q3 stale |
| Qube Research & Technologies Ltd trimmed | 64,825 | $11M | 0.2% | 2025-Q3 stale |
| Candriam S.C.A. added | 50,000 | $11M | 0.2% | 2025-Q2 stale |
| Kingsview Wealth Management, LLC trimmed | 41,402 | $9M | 0.1% | 2025-Q2 stale |
| BW Gestao de Investimentos Ltda. new | 49,500 | $9M | 0.1% | 2025-Q4 stale |
| OSSIAM trimmed | 40,000 | $9M | 0.1% | 2025-Q2 stale |
| WASATCH ADVISORS LP trimmed | 36,532 | $8M | 0.1% | 2025-Q2 stale |
| ADAGE CAPITAL PARTNERS GP, L.L.C. added | 34,350 | $8M | 0.1% | 2025-Q2 stale |
| TWINBEECH CAPITAL LP added | 34,216 | $8M | 0.1% | 2025-Q2 stale |
| NATIONAL BANK OF CANADA /FI/ added | 33,702 | $8M | 0.1% | 2025-Q2 stale |
| Quadrature Capital Ltd added | 39,174 | $7M | 0.1% | 2025-Q4 stale |
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.