Tetra Tech, Inc. (TTEK) Ownership
TTEK ownership summary
as of October 18, 2026- Institutions
- 104.3% of shares outstanding
- Insiders
- 0.49% of shares outstanding
- Shares outstanding
- 256.0M
- Float
- 254.5M shares available to trade
- Short interest
- 5.22% 11.9M shares short
- Days to cover
- 5.64 short interest up 7.1% vs prior month
- Institutions 104.27%
- Insiders 0.49%
TTEK top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | BlackRock Inc | 11.20% | 28.7M | $995.6M | +1.9M (+7.0%) | June 30, 2026 |
| 2 | Vanguard Portfolio Management, LLC | 4.87% | 12.5M | $432.9M | −175,124 (−1.4%) | June 30, 2026 |
| 3 | Vanguard Capital Management, LLC | 4.58% | 11.7M | $407.1M | +16,587 (+0.1%) | June 30, 2026 |
| 4 | Capital Research & Mgmt Co - Division 3 | 4.55% | 11.7M | $404.5M | +265,971 (+2.3%) | June 30, 2026 |
| 5 | State Street Corp | 3.81% | 9.8M | $338.9M | +125,728 (+1.3%) | June 30, 2026 |
| 6 | FMR Inc | 3.42% | 8.8M | $304.4M | +8.4M (+2,571.3%) | June 30, 2026 |
| 7 | Geode Capital Management, LLC | 2.67% | 6.8M | $237.2M | +1.6M (+31.0%) | June 30, 2026 |
| 8 | Fidelity International Ltd | 2.14% | 5.5M | $190.0M | +639,019 (+13.2%) | June 30, 2026 |
| 9 | Amundi | 1.99% | 5.1M | $177.0M | +349,272 (+7.4%) | June 30, 2026 |
| 10 | Fuller & Thaler Asset Management Inc | 1.92% | 4.9M | $170.9M | +1.6M (+48.5%) | June 30, 2026 |
| 11 | Pictet Asset Manangement SA | 1.86% | 4.8M | $165.2M | −4.9M (−50.7%) | June 30, 2026 |
| 12 | Wellington Management Company LLP | 1.83% | 4.7M | $162.3M | −129,960 (−2.7%) | June 30, 2026 |
| 13 | Dimensional Fund Advisors, Inc. | 1.74% | 4.4M | $154.4M | +656,975 (+17.3%) | June 30, 2026 |
| 14 | Neuberger Berman Group LLC | 1.72% | 4.4M | $153.1M | −2.9M (−39.4%) | June 30, 2026 |
| 15 | Arrowstreet Capital Limited Partnership | 1.72% | 4.4M | $152.6M | +3.9M (+708.5%) | June 30, 2026 |
| 16 | Amvescap Plc. | 1.61% | 4.1M | $142.9M | +1.2M (+40.3%) | June 30, 2026 |
| 17 | AQR Capital Management LLC | 1.61% | 4.1M | $142.8M | +2.6M (+171.5%) | June 30, 2026 |
| 18 | Impax Asset Management Group PLC | 1.54% | 3.9M | $136.5M | +101,667 (+2.7%) | June 30, 2026 |
| 19 | LGT Group Foundation | 1.46% | 3.7M | $130.0M | +583,463 (+18.5%) | June 30, 2026 |
| 20 | NORGES BANK | 1.26% | 3.2M | $112.2M | −202,587 (−5.9%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 15 holders added 23.9M shares and 5 cut 8.3M.
TTEK top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | iShares Core S&P Mid-Cap ETF | 3.56% | 9.1M | $316.7M | −3,252 (−0.0%) | September 30, 2026 |
| 2 | Vanguard MStar Total Stk Mkt Idx Invest | 3.22% | 8.2M | $286.3M | −30,482 (−0.4%) | August 31, 2026 |
| 3 | Vanguard Small Cap Index | 2.25% | 5.8M | $200.0M | −211,124 (−3.5%) | September 30, 2026 |
| 4 | FullerThaler Behavioral Sm-Cp Eq R6 | 1.84% | 4.7M | $163.2M | +1.4M (+41.4%) | June 30, 2026 |
| 5 | Strategic Advisers Fidelity US TtlStk | 1.63% | 4.2M | $145.2M | +63,363 (+1.5%) | August 31, 2026 |
| 6 | Vanguard MStar Small Cap Value Index | 1.46% | 3.8M | $130.2M | −41,364 (−1.1%) | September 30, 2026 |
| 7 | Pictet-Water I EUR | 1.25% | 3.2M | $110.9M | −3.6M (−53.2%) | June 30, 2026 |
| 8 | Fidelity Series Value Discovery | 1.13% | 2.9M | $100.1M | −134,300 (−4.5%) | August 31, 2026 |
| 9 | American Funds SMALLCAP World A | 1.03% | 2.6M | $91.5M | −847,845 (−24.3%) | September 30, 2026 |
| 10 | Global X US Infrastructure Dev ETF | 0.83% | 2.1M | $74.1M | +15,120 (+0.7%) | September 30, 2026 |
| 11 | Invesco S&P MidCap Quality ETF | 0.78% | 2.0M | $69.0M | +2,075 (+0.1%) | September 30, 2026 |
| 12 | RobecoSAM Sustainable Water B EUR | 0.77% | 2.0M | $68.8M | −191,114 (−8.8%) | August 31, 2026 |
| 13 | BNP Paribas Aqua C C | 0.75% | 1.9M | $66.7M | −273 (−0.0%) | August 31, 2026 |
| 14 | BNP Paribas Aqua I | 0.74% | 1.9M | $66.2M | −172 (−0.0%) | August 31, 2026 |
| 15 | State Street® SPDR® S&P MIDCAP 400® ETF | 0.74% | 1.9M | $65.7M | −4,768 (−0.3%) | September 30, 2026 |
| 16 | Fidelity World A-Dis-EUR | 0.68% | 1.7M | $60.3M | +1,587 (+0.1%) | August 31, 2026 |
| 17 | American Funds Growth Fd of Amer A | 0.64% | 1.6M | $57.2M | — | September 30, 2026 |
| 18 | Neuberger Global Equity Mgtrnd USD IAcc | 0.64% | 1.6M | $57.0M | −126,935 (−7.2%) | August 31, 2026 |
| 19 | Amundi MSCI Water UCITS ETF Dist | 0.63% | 1.6M | $56.0M | — | September 29, 2026 |
| 20 | First Trust Water ETF | 0.59% | 1.5M | $52.0M | — | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
TTEK insider transactions
latest 2| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-02-04 | Brian N Carter | Sell | $40.23 | 9,979 | $401,455 |
| 2025-08-14 | Gary Birkenbeuel | Sell | $36.00 | 2,390 | $86,040 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
TTEK shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns TTEK
Institutional investors own 104.3% of Tetra Tech's shares and insiders 0.49%. The largest holder is BlackRock Inc with 11.20% of the shares (28.7M), as of June 30, 2026. Among the top 20 institutions, 15 added shares and 5 reduced their stake in the latest filings. Short interest is 5.22% of the float, or 5.64 days of average trading volume. The share count fell 16.7% since 2014.
Related: TTEK analyst forecast, TTEK key metrics, TTEK dividend history. See the TTEK stock overview for the latest quote and news.
TTEK ownership FAQ
Who owns the most Tetra Tech stock?
The largest shareholders of Tetra Tech are BlackRock Inc (11.20%), Vanguard Portfolio Management, LLC (4.87%), Vanguard Capital Management, LLC (4.58%), Capital Research & Mgmt Co - Division 3 (4.55%), State Street Corp (3.81%).
What percentage of Tetra Tech is owned by institutions?
Institutions hold 104.3% of Tetra Tech's shares outstanding; insiders hold 0.49%.
Which funds own Tetra Tech?
The largest fund holders of Tetra Tech are iShares Core S&P Mid-Cap ETF (3.56%), Vanguard MStar Total Stk Mkt Idx Invest (3.22%), Vanguard Small Cap Index (2.25%), FullerThaler Behavioral Sm-Cp Eq R6 (1.84%), Strategic Advisers Fidelity US TtlStk (1.63%).
What is Tetra Tech's short interest?
11.9M shares of Tetra Tech were sold short, 5.22% of the float; at the average daily volume it would take 5.64 days to cover.
Are insiders buying or selling Tetra Tech?
Of the latest 2 reported insider transactions in Tetra Tech (since August 14, 2025), 0 were purchases and 2 were sales.
How many shares of Tetra Tech are outstanding?
Tetra Tech has 256.0M shares outstanding, of which 254.5M are in the public float.