As of November 6, 2026, 2 holders' latest Schedule 13D or 13G filings report owning 5% or more of Onestream Inc. The largest reported stake is Thomas Anthony Shea's, at 16.3%. 15 filings are on record since July 7, 2025 (Schedule 13G/A, February 13, 2026).
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Key facts
- · Holder: Darlington Partners Capital Management, LP · Percent: 0% · SCHEDULE 13G/A
- · Holder: T. Rowe Price Investment Management, Inc. · Percent: 0% · SCHEDULE 13G/A
- · Holder: Kayne Anderson Rudnick Investment Management, LLC · Percent: 0% · SCHEDULE 13G/A
- · Holder: Norges Bank · Percent: 0.18% · SCHEDULE 13G/A
- · Holder: The Vanguard Group · Percent: 0% · SCHEDULE 13G/A
Onestream Inc has 15 Schedule 13D or 13G filings on record since 2025-07-07. 2 holders' latest filing reports 5% or more of common stock. Each figure below is the holder's own, as filed, with the filing linked.
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| 16.3% | 18,173,259 | SCHEDULE 13G/A, 2026-02-13 | 2025-12-31 | |
| Glazer Capital, LLC | 6.83% | 6,166,406 | SCHEDULE 13G, 2026-02-09 | 2026-02-02 |
| Champlain Investment Partners, LLC | 3.3% | 2,886,232 | SCHEDULE 13G, 2026-02-12 | 2025-09-30 |
| Norges Bank | 0.18% | 181,642 | SCHEDULE 13G/A, 2026-05-11 | 2026-03-31 |
| The Vanguard Group | 0% | 0 | SCHEDULE 13G/A, 2026-03-27 | 2026-03-13 |
| Kayne Anderson Rudnick Investment Management, LLC | 0% | 0 | SCHEDULE 13G/A, 2026-05-14 | 2026-03-31 |
| T. Rowe Price Investment Management, Inc. | 0% | 111 | SCHEDULE 13G/A, 2026-05-15 | 2026-03-31 |
| Darlington Partners Capital Management, LP | 0% | 0 | SCHEDULE 13G/A, 2026-05-15 | 2026-03-31 |
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Keep reading
More on Onestream Inc and the records around it.
Onestream Inc elsewhere on the record
- IPO filing Nov 2024
Companies that share a holder
- Darlington Partners Capital Management, LP also filed stake reports on 4 other companies: Six Flags Entertainment Corporation/NEW (Aug 2026), Shift4 Payments, Inc. (May 2026), Warner Music Group Corp. (Apr 2026)
- Champlain Investment Partners, LLC also filed stake reports on 6 other companies: Baldwin Insurance Group, Inc. (Feb 2026), Freshpet, Inc. (Feb 2026), SI-BONE, Inc. (Feb 2026)
- Norges Bank also filed stake reports on 36 other companies: Atour Lifestyle Holdings Ltd (Aug 2026), BXP, Inc. (Aug 2026), Cabaletta Bio, Inc. (Aug 2026)
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What They Do, And How The Money Works
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Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-07-07 | The Vanguard Group | 10.37% | SCHEDULE 13G/A |
| 2025-07-28 | Norges Bank | 8.4% | SCHEDULE 13G/A |
| 2025-11-03 | Norges Bank | 9.7% | SCHEDULE 13G/A |
| 2025-11-13 | Kayne Anderson Rudnick Investment Management, LLC | 7% | SCHEDULE 13G/A |
| 2026-01-26 | Norges Bank | 6.6% | SCHEDULE 13G/A |
| 2026-02-09 | Glazer Capital, LLC | 6.83% | SCHEDULE 13G |
| 2026-02-12 | Champlain Investment Partners, LLC | 3.3% | SCHEDULE 13G |
| 2026-02-13 | Kayne Anderson Rudnick Investment Management, LLC | 5.4% | SCHEDULE 13G/A |
| 2026-02-13 | Thomas Anthony Shea | 16.3% | SCHEDULE 13G/A |
| 2026-02-17 | T. Rowe Price Investment Management, Inc. | 8.6% | SCHEDULE 13G/A |
| 2026-03-27 | The Vanguard Group | 0% | SCHEDULE 13G/A |
| 2026-05-11 | Norges Bank | 0.18% | SCHEDULE 13G/A |
| 2026-05-14 | Kayne Anderson Rudnick Investment Management, LLC | 0% | SCHEDULE 13G/A |
| 2026-05-15 | Darlington Partners Capital Management, LP | 0% | SCHEDULE 13G/A |
| 2026-05-15 | T. Rowe Price Investment Management, Inc. | 0% | SCHEDULE 13G/A |
Questions about who owns Onestream Inc
Who owns Onestream Inc?
On this page, 2 holders' latest ownership filings report 5% or more of Onestream Inc: Thomas Anthony Shea (16.3%, Schedule 13G/A, filed 2026-02-13) and Glazer Capital, LLC (6.83%, Schedule 13G, filed 2026-02-09).
Who are the largest shareholders of Onestream Inc?
By the share each holder's latest filing reports, the largest holders of Onestream Inc on this page are Thomas Anthony Shea (16.3%) and Glazer Capital, LLC (6.83%).
When did Thomas Anthony Shea buy into Onestream Inc?
The filings give report dates, not purchase dates. The earliest filing from Thomas Anthony Shea on this page is the Schedule 13G/A, filed 2026-02-13, reporting 16.3%. 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%); 15 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.
Also on the record for Onestream Inc
| Date | Record | Figure | Our page | Source |
|---|---|---|---|---|
| November 15, 2024 | IPO filing, Form 424B4 | $20 a share | IPO filings | Source |
| November 12, 2024 | IPO filing, Form S-1 | — | IPO filings | Source |
| July 24, 2024 | IPO filing, Form 424B4 | $20 a share | IPO filings | Source |
| July 15, 2024 | IPO filing, Form S-1/A | $17 to $19 a share | IPO filings | Source |
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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.