As of November 6, 2026, 6 holders' latest Schedule 13D or 13G filings report owning 5% or more of Marketaxess Holdings Inc. The largest reported stake is BlackRock, Inc.'s, at 10.9%. 18 filings are on record since August 6, 2025 (Schedule 13G/A, February 6, 2026).
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Key facts
- · Reporting person: Primecap Management Co · Sole voting: 2,443,323 · Shared voting: 0 · Sole dispositive: 2,462,873 · Shared dispositive: 0 · SCHEDULE 13G/A, 2026-11-05
- · Reporting person: North Reef Capital Management LP · Sole voting: 0 · Shared voting: 3,395,000 · Sole dispositive: 0 · Shared dispositive: 3,395,000 · SCHEDULE 13G/A, 2026-08-14
- · Reporting person: AQR Capital Management, LLC · Sole voting: 0 · Shared voting: 1,947,559 · Sole dispositive: 0 · Shared dispositive: 1,987,288 · SCHEDULE 13G/A, 2026-08-13
- · Holder: Primecap Management Co · Percent: 9.86% · SCHEDULE 13G/A
- · Holder: North Reef Capital Management LP · Percent: 5.27% · SCHEDULE 13G
Marketaxess Holdings Inc has 18 Schedule 13D or 13G filings on record since 2025-08-06. 6 holders' latest filing reports 5% or more of com. Each figure below is the holder's own, as filed, with the filing linked.
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| BlackRock, Inc. | 10.9% | 4,034,537 | SCHEDULE 13G/A, 2026-02-06 | 2026-01-31 |
| North Reef Capital Management LP | 9.55% | 3,395,000 | SCHEDULE 13G/A, 2026-08-14 | 2026-06-30 |
| Primecap Management Co | 7% | 2,462,873 | SCHEDULE 13G/A, 2026-11-05 | 2026-09-30 |
| Vanguard Portfolio Management | 6.09% | 2,168,085 | SCHEDULE 13G, 2026-04-29 | 2026-03-31 |
| AQR Capital Management, LLC | 5.59% | 1,987,288 | SCHEDULE 13G/A, 2026-08-13 | 2026-06-30 |
| Vanguard Capital Management | 5.32% | 1,892,096 | SCHEDULE 13G, 2026-04-30 | 2026-03-31 |
| Fmr LLC | 4.2% | 1,500,929 | SCHEDULE 13G/A, 2026-05-06 | 2026-03-31 |
| T. Rowe Price Investment Management, Inc. | 3.7% | 1,370,694 | SCHEDULE 13G/A, 2025-11-14 | 2025-09-30 |
| The Vanguard Group | 0% | 0 | SCHEDULE 13G/A, 2026-03-27 | 2026-03-13 |
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Keep reading
More on Marketaxess Holdings Inc and the records around it.
Marketaxess Holdings Inc elsewhere on the record
Companies that share a holder
- North Reef Capital Management LP also filed stake reports on 9 other companies: Alkami Technology, Inc. (Aug 2026), i3 Verticals, Inc. (Aug 2026), Seacoast Banking Corporation of Florida (Aug 2026)
- PRIMECAP MANAGEMENT CO/CA/ also filed stake reports on 24 other companies: Xencor Inc (Nov 2026), GRAIL, Inc. (Nov 2026), Pulmonx Corp (Nov 2026)
- T. Rowe Price Investment Management, Inc. also filed stake reports on 167 other companies: CABALETTA BIO INC (Nov 2026), MADISON SQUARE GARDEN SPORTS CORP (Nov 2026), MSG RANGERS CORP (Nov 2026)
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Voting and dispositive power, as filed
| Reporting person | Sole voting | Shared voting | Sole dispositive | Shared dispositive | Filing |
|---|---|---|---|---|---|
| North Reef Capital Management LP | 0 | 3,395,000 | 0 | 3,395,000 | SCHEDULE 13G/A, 2026-08-14 |
| North Reef Capital Management GP LLC | 0 | 3,395,000 | 0 | 3,395,000 | SCHEDULE 13G/A, 2026-08-14 |
| James Hanna, III | 0 | 3,395,000 | 0 | 3,395,000 | SCHEDULE 13G/A, 2026-08-14 |
| Primecap Management Co | 2,443,323 | 0 | 2,462,873 | 0 | SCHEDULE 13G/A, 2026-11-05 |
| AQR Capital Management, LLC | 0 | 1,947,559 | 0 | 1,987,288 | SCHEDULE 13G/A, 2026-08-13 |
| AQR Capital Management Holdings, LLC | 0 | 1,947,559 | 0 | 1,987,288 | SCHEDULE 13G/A, 2026-08-13 |
The latest filing identifies Marketaxess Holdings Inc by CUSIP 57060D108 and gives its principal executive office as 55 HUDSON YARDS, 15TH FLOOR, NEW YORK, NY 10001 (SCHEDULE 13G/A, 2026-11-05).
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-08-06 | Fmr LLC | 6.1% | SCHEDULE 13G/A |
| 2025-10-17 | BlackRock, Inc. | 4.2% | SCHEDULE 13G/A |
| 2025-10-31 | The Vanguard Group | 10.31% | SCHEDULE 13G/A |
| 2025-11-13 | Primecap Management Co | 5.97% | SCHEDULE 13G |
| 2025-11-14 | T. Rowe Price Investment Management, Inc. | 3.7% | SCHEDULE 13G/A |
| 2026-01-21 | BlackRock, Inc. | 9.9% | SCHEDULE 13G |
| 2026-02-06 | BlackRock, Inc. | 10.9% | SCHEDULE 13G/A |
| 2026-02-11 | Primecap Management Co | 8.54% | SCHEDULE 13G/A |
| 2026-02-13 | AQR Capital Management, LLC | 6.88% | SCHEDULE 13G |
| 2026-03-27 | The Vanguard Group | 0% | SCHEDULE 13G/A |
| 2026-04-29 | Vanguard Portfolio Management | 6.09% | SCHEDULE 13G |
| 2026-04-30 | Vanguard Capital Management | 5.32% | SCHEDULE 13G |
| 2026-05-06 | Fmr LLC | 4.2% | SCHEDULE 13G/A |
| 2026-05-15 | North Reef Capital Management LP | 5.27% | SCHEDULE 13G |
| 2026-08-06 | Primecap Management Co | 9.86% | SCHEDULE 13G/A |
| 2026-08-13 | AQR Capital Management, LLC | 5.59% | SCHEDULE 13G/A |
| 2026-08-14 | North Reef Capital Management LP | 9.55% | SCHEDULE 13G/A |
| 2026-11-05 | Primecap Management Co | 7% | SCHEDULE 13G/A |
Questions about who owns Marketaxess Holdings Inc
Who owns Marketaxess Holdings Inc?
On this page, 6 holders' latest ownership filings report 5% or more of Marketaxess Holdings Inc: BlackRock, Inc. (10.9%, Schedule 13G/A, filed 2026-02-06), North Reef Capital Management LP (9.55%, Schedule 13G/A, filed 2026-08-14), Primecap Management Co (7%, Schedule 13G/A, filed 2026-11-05), Vanguard Portfolio Management (6.09%, Schedule 13G, filed 2026-04-29) and AQR Capital Management, LLC (5.59%, Schedule 13G/A, filed 2026-08-13); 1 more is listed above.
Who are the largest shareholders of Marketaxess Holdings Inc?
By the share each holder's latest filing reports, the largest holders of Marketaxess Holdings Inc on this page are BlackRock, Inc. (10.9%), North Reef Capital Management LP (9.55%) and Primecap Management Co (7%).
When did BlackRock, Inc. buy into Marketaxess Holdings Inc?
The filings give report dates, not purchase dates. The earliest filing from BlackRock, Inc. on this page is the Schedule 13G/A, filed 2025-10-17, reporting 4.2%; its latest, Schedule 13G/A filed 2026-02-06, reports 10.9%. That earliest filing is itself an amendment, which updates an earlier report.
Is this an audit or a full list?
Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 18 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.
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Where this comes from
Anyone who comes to own more than 5% of a class of a listed company's voting shares has to tell the SEC. A holder who may seek to change or influence the company files Schedule 13D, and has to say in Item 4, "Purpose of Transaction", what it intends to do. A holder with no such intent, such as many index and passive funds, may file the shorter Schedule 13G. Both are amended when the stake changes, including when it falls below 5%.
Every row here is one of those filings, linked to the filing itself. Percentages and share counts are exactly as the holder filed them, for the holder the filing names; an amendment showing a lower figure is shown as filed. Item 4 text is quoted word for word. Where a 13D's Item 4 contains a sentence stating a definite intent to influence the company, that sentence is marked and quoted; the page does not describe the holder or its motives beyond the words it filed. Nothing here is investment advice.