As of November 6, 2026, one holder's latest Schedule 13D or 13G filing report owning 5% or more of Tetra Tech Inc. The largest reported stake is Vanguard Capital Management's, at 5.23%. 3 filings are on record since October 17, 2025 (Schedule 13G, April 30, 2026).
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Key facts
- · Holder: Vanguard Capital Management · Percent: 5.23% · SCHEDULE 13G
- · Holder: The Vanguard Group · Percent: 0% · SCHEDULE 13G/A
- · Holder: Pictet Asset Management Sa · Percent: 4.9% · SCHEDULE 13D/A
Tetra Tech Inc has 3 Schedule 13D or 13G filings on record since 2025-10-17. 1 holder's 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 |
|---|---|---|---|---|
| Vanguard Capital Management | 5.23% | 13,656,856 | SCHEDULE 13G, 2026-04-30 | 2026-03-31 |
| Pictet Asset Management Sa | 4.9% | 13,006,243 | SCHEDULE 13D/A, 2025-10-17 | 2025-10-16 |
| The Vanguard Group | 0% | 0 | SCHEDULE 13G/A, 2026-03-27 | 2026-03-13 |
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More on Tetra Tech Inc and the records around it.
Companies that share a holder
- PICTET ASSET MANAGEMENT SA also filed stake reports on 4 other companies: Elastic N.V. (Oct 2026), Dynatrace, Inc. (Sep 2026), Fortune Brands Innovations, Inc. (Aug 2026)
- Vanguard Capital Management also filed stake reports on 1495 other companies: A10 Networks Inc (Oct 2026), Altisource Portfolio Solutions SA (Oct 2026), Alto Neuroscience Inc (Oct 2026)
- The Vanguard Group also filed stake reports on 2384 other companies: BellRing Brands, Inc. (Sep 2026), CAL-MAINE FOODS INC (Sep 2026), FTAI Aviation Ltd. (Sep 2026)
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Purpose of Transaction (Item 4)
Pictet Asset Management Sa
The Reporting Person acquired shares of Tetra Tech Inc. as part of its investment strategy, considering the clarity and robustness of the issuer's long-term strategy; the functioning and calibre of governance structures and effective leadership; the financial strength and performance of issuers and the fair valuation of underlying securities; and financially-material sustainability risks & opportunities. The Reporting Person is therefore actively engaging with the Issuer to discuss and promote initiatives that align with these business practices. This engagement is part of the Reporting Person's broader strategy to support companies in enhancing their approach, thereby potentially improving long-term shareholder value. As such, the Reporting Person may seek to influence the Issuer's policies and practices through discussions with the Boards and management of the companies in which we invest. The Reporting Person does not currently have any plans or proposals that would result in a change in control of the Issuer, nor does it intend to acquire additional shares for the purpose of gaining control. However, the Reporting Person reserves the right to change its intentions and take any actions that it deems appropriate in light of its ongoing engagement and evaluation of the Issuer's policies and practices.Item 4 of the SCHEDULE 13D/A filed 2025-10-17
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-10-17 | Pictet Asset Management Sa | 4.9% | SCHEDULE 13D/A |
| 2026-03-27 | The Vanguard Group | 0% | SCHEDULE 13G/A |
| 2026-04-30 | Vanguard Capital Management | 5.23% | SCHEDULE 13G |
Questions about who owns Tetra Tech Inc
Who owns Tetra Tech Inc?
On this page, one holder's latest ownership filing reports 5% or more of Tetra Tech Inc: Vanguard Capital Management (5.23%, Schedule 13G, filed 2026-04-30).
When did Vanguard Capital Management buy into Tetra Tech Inc?
The filings give report dates, not purchase dates. The earliest filing from Vanguard Capital Management on this page is the Schedule 13G, filed 2026-04-30, reporting 5.23%.
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%); 3 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.