Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in MKTX held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | BlackRock, Inc. | 4.1M | $672.3M | +8.8% | 11.466% | 0.01% |
| 2 | PRIMECAP MANAGEMENT CO/CA/ | 3.3M | $552.2M | +5.4% | 9.418% | 0.43% |
| 3 | AQR CAPITAL MANAGEMENT LLC | 2.7M | $442.8M | +4.9% | 7.551% | 0.20% |
| 4 | VANGUARD PORTFOLIO MANAGEMENT LLC | 2.2M | $357.0M | β | 6.088% | 0.02% |
| 5 | North Reef Capital Management LP | 1.9M | $309.3M | +16.5% | 5.276% | 10.65% |
| 6 | VANGUARD CAPITAL MANAGEMENT LLC | 1.6M | $265.5M | β | 4.528% | 0.01% |
| 7 | FMR LLC | 1.5M | $250.7M | -24.2% | 4.275% | 0.01% |
| 8 | STATE STREET CORP | 1.3M | $211.3M | +2.6% | 3.604% | 0.01% |
| 9 | MILLENNIUM MANAGEMENT LLC | 1.2M | $198.9M | β | 3.392% | 0.13% |
| 10 | BANK OF MONTREAL /CAN/ | 1.0M | $168.4M | +7.3% | 2.872% | 0.06% |
| 11 | Neuberger Berman Group LLC | 966K | $159.4M | +75.8% | 2.718% | 0.12% |
| 12 | GEODE CAPITAL MANAGEMENT, LLC | 863K | $142.4M | +3.6% | 2.428% | 0.01% |
| 13 | GUARDCAP ASSET MANAGEMENT Ltd | 643K | $106.4M | -44.2% | 1.810% | 6.09% |
| 14 | DIMENSIONAL FUND ADVISORS LP | 581K | $95.9M | +10.3% | 1.636% | 0.02% |
| 15 | TWO SIGMA INVESTMENTS, LP | 524K | $86.5M | -1.8% | 1.474% | 0.07% |
| 16 | GOLDMAN SACHS GROUP INC | 509K | $84.0M | +194.9% | 1.432% | 0.01% |
| 17 | MORGAN STANLEY | 491K | $80.9M | +15.4% | 1.380% | 0.00% |
| 18 | Findlay Park Partners LLP | 481K | $79.3M | -10.4% | 1.352% | 1.11% |
| 19 | CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 339K | $55.8M | +6.3% | 0.953% | 0.01% |
| 20 | Walleye Capital LLC | 333K | $54.9M | +96.0% | 0.936% | 0.23% |
| 21 | BNP PARIBAS ARBITRAGE, SA | 319K | $52.7M | -15.0% | 0.898% | 0.03% |
| 22 | ARROWSTREET CAPITAL, LIMITED PARTNERSHIP | 295K | $48.7M | +2.3% | 0.831% | 0.03% |
| 23 | RDST Capital LLC | 295K | $48.7M | -5.0% | 0.831% | 4.69% |
| 24 | Bank of New York Mellon Corp | 290K | $47.8M | -2.9% | 0.816% | 0.01% |
| 25 | UBS Group AG | 272K | $44.9M | +167.0% | 0.766% | 0.01% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). β% of Fundβ shows how much of that investorβs total 13F portfolio is invested in MKTX β a direct measure of their conviction.
Filings activity in MKTX during Q1 2026, grouped by how each filer changed its position.
Institutions that opened a new MKTX position in Q1 2026
Institutions that fully closed their MKTX position in Q1 2026
8 quarters of 13F filings Β· Ξ columns show change vs prior quarter
| Quarter | Inst. Holders | Ξ Holders | Ownership % | Ξ Ownership | Total 13F Value | Ξ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 438 | 7.8% | 138.15% | 5.41 pp | $5.94B | 3.8% |
| Q4 2025 | 475 | +9.2% | 143.56% | +10.13 pp | $6.17B | +7.6% |
| Q3 2025 | 435 | 16% | 133.43% | 34.03 pp | $5.73B | 20% |
| Q2 2025 | 516 | +4.0% | 167.46% | +11.58 pp | $7.19B | +7.4% |
| Q1 2025 | 496 | 1.0% | 155.88% | 27.79 pp | $6.70B | 15% |
| Q4 2024 | 501 | +1.6% | 183.67% | +0.13 pp | $7.89B | +0.1% |
| Q3 2024 | 493 | +8.6% | 183.54% | +13.96 pp | $7.89B | +8.2% |
| Q2 2024 | 454 | β | 169.58% | β | $7.29B | β |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Ξ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying MKTX stock.
Based on Q1 2026 13F filings, institutional ownership of MarketAxess Holdings Inc. stands at 138.2%, held across 438 reporting institutions.
BlackRock, Inc. is the largest reported institutional holder of MKTX, with approximately 4,075,154 shares worth $0.67B as of Q1 2026.
Yes β 2 widely-followed marquee investors appear among the top 25 institutional holders of MKTX, including MILLENNIUM MANAGEMENT LLC, TWO SIGMA INVESTMENTS, LP.
Our composite Smart Money Score for MKTX is 34 out of 100 (Bearish). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
65 institutions opened new positions in MKTX during Q1 2026, while 102 fully exited. 123 added to existing positions and 246 trimmed.
MKTX institutional ownership fell by 5.41 percentage points quarter-over-quarter, with a net change of -37 holders.
The top 10 institutions account for 57.8% of all reported 13F value in MKTX, and the top 25 account for 77.8%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
MarketAxess Holdings Inc. (MKTX) Institutional Ownership