MARKETAXESS HLDGS INC (MKTX): Ownership & Insider Activity
Hedge funds and institutional managers reporting a position in MKTX · Financials. Based on the most recent 13F filing from each holder, sourced from SEC EDGAR.
Reported Holders
26
13F filers
Aggregate Value
$851.0M
Across holders
Last Price
$162.46
2026-08-24
Sector
Financials
GICS
Quarterly fund activity15 increased11 reduced1 exited
Full exits: BAILLIE GIFFORD & CO
| Manager⇅ | Type⇅ | Shares⇅ | Market Value▼ | % of Total⇅ | % of Portfolio⇅ | Action⇅ | QoQ Change⇅ | Quarter⇅ |
|---|---|---|---|---|---|---|---|---|
| PRIMECAP MANAGEMENT CO/CA/ CIK 0000763212 | Institutional Manager | 3.50M | $397.8M | 46.7% | 0.2% | Added | +$17.9M | Q2 2026 |
| AQR CAPITAL MANAGEMENT LLC CIK 0001167557 | Hedge Fund | 1.99M | $222.8M | 26.2% | 0.1% | Reduced | +$222.7M | Q2 2026 |
| TWO SIGMA INVESTMENTS, LP CIK 0001179392 | Hedge Fund | 544K | $61.7M | 7.3% | 0.0% | Added | +$2.3M | Q2 2026 |
| CITADEL ADVISORS LLC CIK 0001423053 | Hedge Fund | 482K | $54.7M | 6.4% | 0.0% | Added | +$49.9M | Q2 2026 |
| RENAISSANCE TECHNOLOGIES LLC CIK 0001037389 | Hedge Fund | 200K | $22.7M | 2.7% | 0.0% | Added | +$3.7M | Q2 2026 |
| TUDOR INVESTMENT CORP ET AL CIK 0000923093 | Hedge Fund | 138K | $15.6M | 1.8% | 0.0% | Added | — | Q2 2026 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP CIK 0001164508 | Hedge Fund | 122K | $13.8M | 1.6% | 0.0% | Reduced | $-19.7M | Q2 2026 |
| MILLENNIUM MANAGEMENT LLC CIK 0001273087 | Hedge Fund | 110K | $12.4M | 1.5% | 0.0% | Reduced | $-977K | Q2 2026 |
| Walleye Capital LLC CIK 0001758720 | Hedge Fund | 94K | $10.7M | 1.3% | 0.0% | Reduced | +$10.7M | Q2 2026 |
| Brevan Howard Capital Management LP CIK 0001512857 | Hedge Fund | 51K | $5.8M | 0.7% | 0.0% | Added | — | Q2 2026 |
Added
Institutional Manager
$397.8M· 46.7% of total· 0.2% port· 3.50M sh· +$17.9M QoQ· Q2 2026
Reduced
Hedge Fund
$222.8M· 26.2% of total· 0.1% port· 1.99M sh· +$222.7M QoQ· Q2 2026
Added
Hedge Fund
$61.7M· 7.3% of total· 0.0% port· 544K sh· +$2.3M QoQ· Q2 2026
Added
Hedge Fund
$54.7M· 6.4% of total· 0.0% port· 482K sh· +$49.9M QoQ· Q2 2026
Added
Hedge Fund
$22.7M· 2.7% of total· 0.0% port· 200K sh· +$3.7M QoQ· Q2 2026
Added
Hedge Fund
$15.6M· 1.8% of total· 0.0% port· 138K sh· — QoQ· Q2 2026
Reduced
Hedge Fund
$13.8M· 1.6% of total· 0.0% port· 122K sh· $-19.7M QoQ· Q2 2026
Reduced
Hedge Fund
$12.4M· 1.5% of total· 0.0% port· 110K sh· $-977K QoQ· Q2 2026
Reduced
Hedge Fund
$10.7M· 1.3% of total· 0.0% port· 94K sh· +$10.7M QoQ· Q2 2026
Added
Hedge Fund
$5.8M· 0.7% of total· 0.0% port· 51K sh· — QoQ· Q2 2026
Added
Institutional Manager
$5.6M· 0.7% of total· 0.0% port· 50K sh· +$5.6M QoQ· Q2 2026
Added
Hedge Fund
$5.4M· 0.6% of total· 0.0% port· 48K sh· +$5.1M QoQ· Q2 2026
Added
Hedge Fund
$4.4M· 0.5% of total· 0.0% port· 39K sh· — QoQ· Q2 2026
Reduced
Hedge Fund
$4.3M· 0.5% of total· 0.0% port· 38K sh· $-628K QoQ· Q2 2026
Added
Hedge Fund
$3.7M· 0.4% of total· 0.0% port· 32K sh· +$1.9M QoQ· Q2 2026
Added
Hedge Fund
$1.6M· 0.2% of total· 0.0% port· 14K sh· +$1.4M QoQ· Q2 2026
Added
Hedge Fund
$1.5M· 0.2% of total· 0.0% port· 13K sh· — QoQ· Q2 2026
Reduced
Hedge Fund
$1.3M· 0.2% of total· 0.0% port· 12K sh· $-5.5M QoQ· Q2 2026
Reduced
Hedge Fund
$1.3M· 0.2% of total· 0.0% port· 11K sh· $-22K QoQ· Q2 2026
Added
Hedge Fund
$1.2M· 0.1% of total· 0.0% port· 11K sh· — QoQ· Q2 2026
Reduced
Hedge Fund
$919K· 0.1% of total· 0.0% port· 8K sh· $-27.8M QoQ· Q2 2026
Added
Hedge Fund
$797K· 0.1% of total· 0.0% port· 7K sh· +$161K QoQ· Q2 2026
Reduced
Hedge Fund
$557K· 0.1% of total· 0.0% port· 5K sh· $-4.3M QoQ· Q2 2026
Reduced
Hedge Fund
$244K· 0.0% of total· 0.0% port· 2K sh· +$202K QoQ· Q2 2026
Reduced
Hedge Fund
$4K· 0.0% of total· 0.0% port· 31 sh· $-16K QoQ· Q2 2026
Added
Hedge Fund
$2K· 0.0% of total· 0.0% port· 22 sh· — QoQ· Q2 2026
1–10 of 26
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