As of November 6, 2026, 4 holders' latest Schedule 13D or 13G filings report owning 5% or more of iRhythm Holdings, Inc. The largest reported stake is RTW Investments, LP's, at 6.6%. 13 filings are on record since August 13, 2025 (Schedule 13G/A, August 14, 2026).
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Key facts
- · Reporting person: Millennium Management LLC · Sole voting: 0 · Shared voting: 349,087 · Sole dispositive: 0 · Shared dispositive: 349,087 · SCHEDULE 13G/A, 2026-10-13
- · Reporting person: RTW Investments, LP · Sole voting: 0 · Shared voting: 2,182,631 · Sole dispositive: 0 · Shared dispositive: 2,182,631 · SCHEDULE 13G/A, 2026-08-14
- · Reporting person: Artisan Partners Asset Management Inc. · Sole voting: 0 · Shared voting: 1,529,086 · Sole dispositive: 0 · Shared dispositive: 1,660,307 · SCHEDULE 13G, 2026-08-13
- · Holder: RTW Investments, LP · Percent: 5.2% · SCHEDULE 13G
- · Holder: Sands Capital Management, LLC · Percent: 0% · SCHEDULE 13G/A
iRhythm Holdings, Inc. has 13 Schedule 13D or 13G filings on record since 2025-08-13. 4 holders' latest filing reports 5% or more of common stock, par value $0.001 per share. Each figure below is the holder's own, as filed, with the filing linked.
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| RTW Investments, LP | 6.6% | 2,182,631 | SCHEDULE 13G/A, 2026-08-14 | 2026-06-30 |
| Vanguard Portfolio Management | 5.64% | 1,824,090 | SCHEDULE 13G, 2026-04-28 | 2026-03-31 |
| Vanguard Capital Management | 5.23% | 1,691,483 | SCHEDULE 13G, 2026-04-27 | 2026-03-31 |
| Artisan Partners Asset Management Inc. | 5.1% | 1,660,307 | SCHEDULE 13G, 2026-08-13 | 2026-06-30 |
| Capital Research Global Investors | 4.7% | 1,506,864 | SCHEDULE 13G/A, 2025-08-13 | 2025-06-30 |
| Millennium Management LLC | 1.1% | 349,087 | SCHEDULE 13G/A, 2026-10-13 | 2026-09-30 |
| Sands Capital Management, LLC | 0% | 0 | SCHEDULE 13G/A, 2026-05-08 | 2026-03-31 |
| The Vanguard Group | 0% | 0 | SCHEDULE 13G/A, 2026-03-26 | 2026-03-13 |
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More on iRhythm Holdings, Inc. and the records around it.
iRhythm Holdings, Inc. elsewhere on the record
Companies that share a holder
- SANDS CAPITAL MANAGEMENT, LLC also filed stake reports on 1 other company: Samsara Inc. (May 2026)
- Artisan Partners Asset Management Inc. also filed stake reports on 16 other companies: Ascendis Pharma A/S (Aug 2026), AXALTA COATING SYSTEMS LTD. (Aug 2026), RADWARE LTD. (Aug 2026)
- RTW Investments, LP also filed stake reports on 43 other companies: CG Oncology, Inc. (Aug 2026), Kailera Therapeutics, Inc. (Aug 2026), ORUKA THERAPEUTICS, INC. (Aug 2026)
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Voting and dispositive power, as filed
| Reporting person | Sole voting | Shared voting | Sole dispositive | Shared dispositive | Filing |
|---|---|---|---|---|---|
| RTW Investments, LP | 0 | 2,182,631 | 0 | 2,182,631 | SCHEDULE 13G/A, 2026-08-14 |
| Roderick Wong | 0 | 2,182,631 | 0 | 2,182,631 | SCHEDULE 13G/A, 2026-08-14 |
| Artisan Partners Asset Management Inc. | 0 | 1,529,086 | 0 | 1,660,307 | SCHEDULE 13G, 2026-08-13 |
| Artisan Partners Holdings LP | 0 | 1,529,086 | 0 | 1,660,307 | SCHEDULE 13G, 2026-08-13 |
| Artisan Investments GP LLC | 0 | 1,529,086 | 0 | 1,660,307 | SCHEDULE 13G, 2026-08-13 |
| Artisan Partners Limited Partnership | 0 | 1,529,086 | 0 | 1,660,307 | SCHEDULE 13G, 2026-08-13 |
| Millennium Management LLC | 0 | 349,087 | 0 | 349,087 | SCHEDULE 13G/A, 2026-10-13 |
| Millennium Group Management LLC | 0 | 349,087 | 0 | 349,087 | SCHEDULE 13G/A, 2026-10-13 |
| Israel A. Englander | 0 | 349,087 | 0 | 349,087 | SCHEDULE 13G/A, 2026-10-13 |
The latest filing identifies iRhythm Holdings, Inc. by CUSIP 450056106 and gives its principal executive office as 699 8th Street, Suite 600, San Francisco, CA 94103 (SCHEDULE 13G/A, 2026-10-13).
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-08-13 | Capital Research Global Investors | 4.7% | SCHEDULE 13G/A |
| 2025-11-13 | Sands Capital Management, LLC | 6.9% | SCHEDULE 13G/A |
| 2026-02-03 | Artisan Partners Asset Management Inc. | 4.7% | SCHEDULE 13G/A |
| 2026-02-13 | Sands Capital Management, LLC | 5.3% | SCHEDULE 13G/A |
| 2026-03-23 | Millennium Management LLC | 5.1% | SCHEDULE 13G |
| 2026-03-26 | The Vanguard Group | 0% | SCHEDULE 13G/A |
| 2026-04-27 | Vanguard Capital Management | 5.23% | SCHEDULE 13G |
| 2026-04-28 | Vanguard Portfolio Management | 5.64% | SCHEDULE 13G |
| 2026-05-08 | Sands Capital Management, LLC | 0% | SCHEDULE 13G/A |
| 2026-05-15 | RTW Investments, LP | 5.2% | SCHEDULE 13G |
| 2026-08-13 | Artisan Partners Asset Management Inc. | 5.1% | SCHEDULE 13G |
| 2026-08-14 | RTW Investments, LP | 6.6% | SCHEDULE 13G/A |
| 2026-10-13 | Millennium Management LLC | 1.1% | SCHEDULE 13G/A |
Questions about who owns iRhythm Holdings, Inc.
Who owns iRhythm Holdings, Inc.?
On this page, 4 holders' latest ownership filings report 5% or more of iRhythm Holdings, Inc.: RTW Investments, LP (6.6%, Schedule 13G/A, filed 2026-08-14), Vanguard Portfolio Management (5.64%, Schedule 13G, filed 2026-04-28), Vanguard Capital Management (5.23%, Schedule 13G, filed 2026-04-27) and Artisan Partners Asset Management Inc. (5.1%, Schedule 13G, filed 2026-08-13).
Who are the largest shareholders of iRhythm Holdings, Inc.?
By the share each holder's latest filing reports, the largest holders of iRhythm Holdings, Inc. on this page are RTW Investments, LP (6.6%), Vanguard Portfolio Management (5.64%) and Vanguard Capital Management (5.23%).
When did RTW Investments, LP buy into iRhythm Holdings, Inc.?
The filings give report dates, not purchase dates. The earliest filing from RTW Investments, LP on this page is the Schedule 13G, filed 2026-05-15, reporting 5.2%; its latest, Schedule 13G/A filed 2026-08-14, reports 6.6%.
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%); 13 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.