As of November 6, 2026, 3 holders' latest Schedule 13D or 13G filings report owning 5% or more of Ceco Environmental Corp. The largest reported stake is Jason DeZwirek's, at 11.7%. 13 filings are on record since July 16, 2025 (Schedule 13D/A, February 26, 2026).
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Key facts
- · Reporting person: Fmr LLC · Sole voting: 3,750,284 · Shared voting: 0 · Sole dispositive: 3,752,936 · Shared dispositive: 0 · SCHEDULE 13G/A, 2026-11-05
- · Reporting person: T. Rowe Price Investment Management, Inc. · Sole voting: 2,147,618 · Shared voting: 0 · Sole dispositive: 2,153,953 · Shared dispositive: 0 · SCHEDULE 13G/A, 2026-08-14
- · Reporting person: American Century Investment Management, Inc. · Sole voting: 1,564,938 · Shared voting: 0 · Sole dispositive: 2,088,421 · Shared dispositive: 0 · SCHEDULE 13G/A, 2026-08-14
- · Holder: Fmr LLC · Percent: 7.7% · SCHEDULE 13G/A
- · Holder: T. Rowe Price Investment Management, Inc. · Percent: 6% · SCHEDULE 13G
Ceco Environmental Corp has 13 Schedule 13D or 13G filings on record since 2025-07-16. 3 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 |
|---|---|---|---|---|
| 11.7% | 4,198,111 | SCHEDULE 13D/A, 2026-02-26 | 2026-02-23 | |
| Fmr LLC | 6.4% | 3,752,936 | SCHEDULE 13G/A, 2026-11-05 | 2026-09-30 |
| BlackRock, Inc. | 6.3% | 2,221,551 | SCHEDULE 13G/A, 2025-07-16 | 2025-06-30 |
| The Vanguard Group | 4.99% | 1,780,596 | SCHEDULE 13G/A, 2026-01-30 | 2025-12-31 |
| Capital International Investors | 4.7% | 1,675,351 | SCHEDULE 13G/A, 2025-11-13 | 2025-09-30 |
| T. Rowe Price Investment Management, Inc. | 3.7% | 2,153,953 | SCHEDULE 13G/A, 2026-08-14 | 2026-06-30 |
| American Century Investment Management, Inc. | 3.6% | 2,088,421 | SCHEDULE 13G/A, 2026-08-14 | 2026-06-30 |
| Hood River Capital Management LLC | 1.39% | 492,374 | SCHEDULE 13G/A, 2025-11-14 | 2025-09-30 |
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More on Ceco Environmental Corp and the records around it.
Ceco Environmental Corp elsewhere on the record
- Acquisition Jun 2026
- Leadership changes Jun 2026
- Who owns it
Companies that share a holder
- Hood River Capital Management LLC also filed stake reports on 19 other companies: Butterfly Network Inc. (Aug 2026), Camping World Holdings, Inc. (Aug 2026), Kura Sushi USA Inc. (Aug 2026)
- American Century Investment Management, Inc. also filed stake reports on 83 other companies: Visteon Corporation (Oct 2026), MarineMax, Inc. (Sep 2026), AdvanSix Inc. (Aug 2026)
- Capital International Investors also filed stake reports on 96 other companies: Aurora Innovation, Inc. (Nov 2026), Arxis, Inc. (Aug 2026), Astronics Corp. (Aug 2026)
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Voting and dispositive power, as filed
| Reporting person | Sole voting | Shared voting | Sole dispositive | Shared dispositive | Filing |
|---|---|---|---|---|---|
| Fmr LLC | 3,750,284 | 0 | 3,752,936 | 0 | SCHEDULE 13G/A, 2026-11-05 |
| Abigail P. Johnson | 0 | 0 | 3,752,936 | 0 | SCHEDULE 13G/A, 2026-11-05 |
| T. Rowe Price Investment Management, Inc. | 2,147,618 | 0 | 2,153,953 | 0 | SCHEDULE 13G/A, 2026-08-14 |
| American Century Investment Management, Inc. | 1,564,938 | 0 | 2,088,421 | 0 | SCHEDULE 13G/A, 2026-08-14 |
| American Century Companies, Inc. | 1,564,938 | 0 | 2,088,421 | 0 | SCHEDULE 13G/A, 2026-08-14 |
| Stowers Institute for Medical Research | 1,564,938 | 0 | 2,088,421 | 0 | SCHEDULE 13G/A, 2026-08-14 |
The latest filing identifies Ceco Environmental Corp by CUSIP 125141101 and gives its principal executive office as 5080 SPECTRUM DRIVE, SUITE 800E, ADDISON, TX 75001 (SCHEDULE 13G/A, 2026-11-05).
Purpose of Transaction (Item 4)
Jason DeZwirek
Item 4 of the Schedule 13D is hereby amended and supplemented by adding the following at the end thereof: On February 23, 2026, the Issuer, Longhorn Merger Sub Inc., a Delaware corporation and wholly owned subsidiary of the Issuer ("Merger Sub Inc."), and Longhorn Merger Sub LLC, a Delaware limited liability company and wholly owned subsidiary of the Issuer ("Merger Sub LLC"), and Thermon Group Holdings, Inc., a Delaware corporation ("Thermon") entered into an Agreement and Plan of Merger, dated as of February 23, 2026 (the "Merger Agreement"), which provided for, among other things, (i) the merger of Merger Sub Inc. with and into Thermon, with Thermon continuing as the surviving entity (the "Surviving Corporation") (the "First Merger") and (ii) immediately following the First Merger, the merger of the Surviving Corporation with and into Merger Sub LLC, with Merger Sub LLC continuing as the surviving entity (the "Surviving Company") (together with the First Merger, the "Mergers"). Concurrently with the execution of the Merger Agreement, on February 23, 2026, the Reporting Persons entered into a Voting Agreement with the Issuer and Thermon (the "Voting Agreement"), pursuant to which the Reporting Persons have agreed, among other things and subject to certain restrictions, (i) not to transfer any of the (A) 2,770,546 shares of Common Stock of which Icarus is a record owner, (B) 200,000 shares of Common Stock of which 0to100 is a record owner or (C) 4,198,111 of the shares of …The first part of Item 4 of the SCHEDULE 13D/A filed 2026-02-26; the filing has the rest
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-07-16 | BlackRock, Inc. | 6.3% | SCHEDULE 13G/A |
| 2025-08-06 | Fmr LLC | 6.2% | SCHEDULE 13G/A |
| 2025-10-30 | The Vanguard Group | 5.01% | SCHEDULE 13G |
| 2025-11-13 | Capital International Investors | 4.7% | SCHEDULE 13G/A |
| 2025-11-14 | Hood River Capital Management LLC | 1.39% | SCHEDULE 13G/A |
| 2026-01-30 | The Vanguard Group | 4.99% | SCHEDULE 13G/A |
| 2026-02-13 | American Century Investment Management, Inc. | 5.7% | SCHEDULE 13G |
| 2026-02-26 | Jason DeZwirek | 11.7% | SCHEDULE 13D/A |
| 2026-05-15 | T. Rowe Price Investment Management, Inc. | 6% | SCHEDULE 13G |
| 2026-08-06 | Fmr LLC | 7.7% | SCHEDULE 13G/A |
| 2026-08-14 | American Century Investment Management, Inc. | 3.6% | SCHEDULE 13G/A |
| 2026-08-14 | T. Rowe Price Investment Management, Inc. | 3.7% | SCHEDULE 13G/A |
| 2026-11-05 | Fmr LLC | 6.4% | SCHEDULE 13G/A |
Questions about who owns Ceco Environmental Corp
Who owns Ceco Environmental Corp?
On this page, 3 holders' latest ownership filings report 5% or more of Ceco Environmental Corp: Jason DeZwirek (11.7%, Schedule 13D/A, filed 2026-02-26), Fmr LLC (6.4%, Schedule 13G/A, filed 2026-11-05) and BlackRock, Inc. (6.3%, Schedule 13G/A, filed 2025-07-16).
Who are the largest shareholders of Ceco Environmental Corp?
By the share each holder's latest filing reports, the largest holders of Ceco Environmental Corp on this page are Jason DeZwirek (11.7%), Fmr LLC (6.4%) and BlackRock, Inc. (6.3%).
When did Jason DeZwirek buy into Ceco Environmental Corp?
The filings give report dates, not purchase dates. The earliest filing from Jason DeZwirek on this page is the Schedule 13D/A, filed 2026-02-26, reporting 11.7%. 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%); 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.
Also on the record for Ceco Environmental Corp
| Date | Record | Figure | Our page | Source |
|---|---|---|---|---|
| June 1, 2026 | Acquired Thermon | $329.40M | Acquisition | Source |
| June 1, 2026 | Leadership change: Marcus J. George appointed, Chairman of the Board, and 1 more | — | Leadership changes | 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.