Ranked by reported Q2 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. | 4.0M | $453.9M | -1.8% | 11.366% | 0.01% |
| 2 | PRIMECAP MANAGEMENT CO/CA/ | 3.5M | $397.8M | +4.7% | 9.959% | 0.24% |
| 3 | North Reef Capital Management LP | 3.4M | $385.3M | +81.1% | 9.647% | 14.77% |
| 4 | VANGUARD PORTFOLIO MANAGEMENT LLC | 2.1M | $238.4M | -2.9% | 5.968% | 0.01% |
| 5 | AQR CAPITAL MANAGEMENT LLC | 2.0M | $222.8M | -25.9% | 5.647% | 0.08% |
| 6 | VANGUARD CAPITAL MANAGEMENT LLC | 1.5M | $175.5M | -3.9% | 4.395% | 0.00% |
| 7 | FMR LLC | 1.4M | $159.5M | -7.5% | 3.992% | 0.01% |
| 8 | STATE STREET CORP | 1.3M | $145.4M | +0.1% | 3.642% | 0.00% |
| 9 | Neuberger Berman Group LLC | 1.2M | $139.6M | +27.3% | 3.495% | 0.05% |
| 10 | MILLENNIUM MANAGEMENT LLC | 1.2M | $131.2M | -4.1% | 3.286% | 0.05% |
| 11 | CITIGROUP INC | 1.1M | $120.8M | +4875.5% | 3.024% | 0.04% |
| 12 | GOLDMAN SACHS GROUP INC | 1.0M | $117.0M | +102.6% | 2.930% | 0.01% |
| 13 | BANK OF MONTREAL /CAN/ | 1.0M | $115.4M | -0.4% | 2.890% | 0.04% |
| 14 | GEODE CAPITAL MANAGEMENT, LLC | 995K | $112.9M | +15.3% | 2.827% | 0.01% |
| 15 | VAN ECK ASSOCIATES CORP | 925K | $104.9M | -25.4% | 2.627% | 0.06% |
| 16 | DIMENSIONAL FUND ADVISORS LP | 598K | $67.8M | +2.8% | 1.699% | 0.01% |
| 17 | NORGES BANK | 572K | $65.0M | — | 1.627% | 0.01% |
| 18 | CITADEL ADVISORS LLC | 548K | $62.2M | +347.2% | 1.558% | 0.00% |
| 19 | GUARDCAP ASSET MANAGEMENT Ltd | 536K | $62.2M | -16.6% | 1.524% | 2.21% |
| 20 | TWO SIGMA INVESTMENTS, LP | 544K | $61.7M | +3.8% | 1.546% | 0.04% |
| 21 | Azora Capital LP | 513K | $58.2M | — | 1.458% | 2.45% |
| 22 | Davis Asset Management, L.P. | 500K | $56.7M | +359.4% | 1.421% | 1.44% |
| 23 | JPMORGAN CHASE & CO | 438K | $48.3M | +1.2% | 1.245% | 0.00% |
| 24 | MORGAN STANLEY | 423K | $48.0M | -13.8% | 1.202% | 0.00% |
| 25 | LOS ANGELES CAPITAL MANAGEMENT LLC | 392K | $44.5M | +3992.1% | 1.114% | 0.16% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). “% of Fund” shows how much of that investor’s total 13F portfolio is invested in MKTX — a direct measure of their conviction.
Filings activity in MKTX during Q2 2026, grouped by how each filer changed its position.
8 quarters of 13F filings · Δ columns show change vs prior quarter
| Quarter | Inst. Holders | Δ Holders | Ownership % | Δ Ownership | Total 13F Value | Δ Value |
|---|---|---|---|---|---|---|
| Q2 2026 | 395 | 11% | 117.46% | +8.41 pp | $4.62B | 23% |
| Q1 2026 | 444 | 7.1% | 109.05% | +5.57 pp | $6.03B | 3.3% |
| Q4 2025 | 478 | +8.9% | 103.48% | 8.92 pp | $6.23B | +8.6% |
| Q3 2025 | 439 | 15% | 112.40% | +13.39 pp | $5.74B | 20% |
| Q2 2025 | 516 | +4.0% | 99.01% | +1.69 pp | $7.19B | +7.4% |
| Q1 2025 | 496 | 1.0% | 97.32% | 3.00 pp | $6.70B | 15% |
| Q4 2024 | 501 | +1.6% | 100.32% | +4.21 pp | $7.89B | +0.1% |
| Q3 2024 | 493 | — | 96.11% | — | $7.89B | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying MKTX stock.
Based on Q2 2026 13F filings, institutional ownership of MarketAxess Holdings Inc. stands at 117.5%, held across 395 reporting institutions.
BlackRock, Inc. is the largest reported institutional holder of MKTX, with approximately 3,999,836 shares worth $0.45B as of Q2 2026.
Yes — 3 widely-followed marquee investors appear among the top 25 institutional holders of MKTX, including MILLENNIUM MANAGEMENT LLC, CITADEL ADVISORS LLC, TWO SIGMA INVESTMENTS, LP.
Our composite Smart Money Score for MKTX is 58 out of 100 (Neutral). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
50 institutions opened new positions in MKTX during Q2 2026, while 103 fully exited. 60 added to existing positions and 268 trimmed.
MKTX institutional ownership rose by 8.41 percentage points quarter-over-quarter, with a net change of -49 holders.
The top 10 institutions account for 53.1% of all reported 13F value in MKTX, and the top 25 account for 77.9%.
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