Tetra Tech, Inc.
US ˙ NasdaqGS ˙ US88162G1031

SecurityTTEK / Tetra Tech, Inc.
InstitutionNorthern Trust Corp
Latest Disclosed Ownership2,320,311 shares
Latest Disclosed Value $ 69,887,767
Northern Trust Corp reports 1.30% decrease in ownership of TTEK / Tetra Tech, Inc.

On May 14, 2026 - Northern Trust Corp filed a 13F-HR form disclosing ownership of 2,320,311 shares of Tetra Tech, Inc. (US:TTEK) valued at $69,887,767 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 2,350,923 shares of Tetra Tech, Inc.. This represents a change in shares of -1.30% during the quarter. The current value of the position is $64,899,099 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-14 2026-03-31 13F TETRA TECH INC COM 88162G103 2,320,311 -30,612 -1.30 69,888 -11.37 0.0019
2026-02-17 2025-12-31 13F TETRA TECH INC COM 88162G103 2,350,923 -201,284 -7.89 78,850 -7.45 0.0021
2025-11-14 2025-09-30 13F TETRA TECH INC COM 88162G103 2,552,207 -43,497 -1.68 85,193 -8.73 0.0109
2025-08-13 2025-06-30 13F TETRA TECH INC COM 88162G103 2,595,704 -282,704 -9.82 93,342 10.87 0.0128
2025-05-13 2025-03-31 13F TETRA TECH INC COM 88162G103 2,878,408 132,974 4.84 84,193 -23.03 0.0125
2025-02-14 2024-12-31 13F TETRA TECH INC COM 88162G103 2,745,434 482,101 21.30 109,378 2.47 0.0155
2024-11-13 2024-09-30 13F TETRA TECH INC COM 88162G103 2,263,333 1,796,449 384.77 106,739 11.81 0.0175
2024-08-14 2024-06-30 13F TETRA TECH INC COM 88162G103 466,884 45,051 10.68 95,468 22.53 0.0161
2024-05-14 2024-03-31 13F TETRA TECH INC COM 88162G103 421,833 -40,769 -8.81 77,917 0.90 0.0135
2024-02-13 2023-12-31 13F TETRA TECH INC COM 88162G103 462,602 3,311 0.72 77,222 10.59 0.0140
2023-11-13 2023-09-30 13F TETRA TECH INC COM 88162G103 459,291 5,705 1.26 69,826 -5.98 0.0135
2023-08-11 2023-06-30 13F TETRA TECH INC COM 88162G103 453,586 -7,069 -1.53 74,270 9.75 0.0143
2023-05-15 2023-03-31 13F TETRA TECH INC COM 88162G103 460,655 5,427 1.19 67,675 2.39 0.0134
2023-02-13 2022-12-31 13F TETRA TECH INC COM 88162G103 455,228 8,661 1.94 66,095 15.15 0.0139
2022-11-14 2022-09-30 13F TETRA TECH INC COM 88162G103 446,567 -2,137 -0.48 57,396 -6.32 0.0131
2022-08-12 2022-06-30 13F TETRA TECH INC COM 88162G103 448,704 -322,306 -41.80 61,271 -51.82 0.0131
2022-05-13 2022-03-31 13F TETRA TECH INC COM 88162G103 771,010 -18,351 -2.32 127,171 -5.12 0.0224
2022-02-08 2021-12-31 13F TETRA TECH INC COM 88162G103 789,361 -24,729 -3.04 134,034 10.25 0.0220
2021-11-15 2021-09-30 13F TETRA TECH INC COM 88162G103 814,090 657 0.08 121,576 22.47 0.0215
2021-08-13 2021-06-30 13F TETRA TECH INC COM 88162G103 813,433 -10,086 -1.22 99,270 -11.18 0.0175
2021-05-12 2021-03-31 13F TETRA TECH INC COM 88162G103 823,519 -19,479 -2.31 111,768 14.51 0.0208
2021-02-11 2020-12-31 13F TETRA TECH INC COM 88162G103 842,998 -26,350 -3.03 97,603 17.56 0.0190
2020-11-16 2020-09-30 13F TETRA TECH INC COM 88162G103 869,348 -49,398 -5.38 83,022 14.21 0.0182
2020-08-14 2020-06-30 13F TETRA TECH INC COM 88162G103 918,746 -230,871 -20.08 72,691 -10.46 0.0172
2020-05-14 2020-03-31 13F TETRA TECH INC COM 88162G103 1,149,617 10,982 0.96 81,186 -17.25 0.0233
2020-02-14 2019-12-31 13F TETRA TECH INC COM 88162G103 1,138,635 -15,854 -1.37 98,106 -2.05 0.0220
2019-11-13 2019-09-30 13F TETRA TECH INC COM 88162G103 1,154,489 151,087 15.06 100,163 27.08 0.0240
2019-08-13 2019-06-30 13F TETRA TECH INC COM 88162G103 1,003,402 6,739 0.68 78,816 32.71 0.0187
2019-05-13 2019-03-31 13F TETRA TECH INC COM 88162G103 996,663 4,337 0.44 59,391 15.61 0.0147
2019-02-12 2018-12-31 13F TETRA TECH INC COM 88162G103 992,326 -8,377 -0.84 51,373 -24.84 0.0144
2018-11-14 2018-09-30 13F TETRA TECH INC COM 88162G103 1,000,703 -518 -0.05 68,347 16.69 0.0167
2018-09-18 2018-06-30 13F/A-1 TETRA TECH INC COM 88162G103 1,001,221 -16,529 -1.62 58,572 17.57 0.0149
2018-08-14 2018-06-30 13F TETRA TECH INC COM 88162G103 1,004,966 -12,784 58,791
2018-05-09 2018-03-31 13F TETRA TECH INC COM 88162G103 1,017,750 -1,090 -0.11 49,818 1.55 0.0130
2018-02-14 2017-12-31 13F TETRA TECH INC COM 88162G103 1,018,840 -22,528 -2.16 49,058 1.20 0.0124
2017-11-13 2017-09-30 13F TETRA TECH INC COM 88162G103 1,041,368 -34,108 -3.17 48,475 -1.48 0.0126
2017-08-11 2017-06-30 13F TETRA TECH INC COM 88162G103 1,075,476 23,510 2.23 49,203 14.50 0.0138
2017-05-12 2017-03-31 13F TETRA TECH INC COM 88162G103 1,051,966 13,692 1.32 42,972 -4.08 0.0124
2017-02-13 2016-12-31 13F TETRA TECH INC COM 88162G103 1,038,274 -149,276 -12.57 44,802 6.36 0.0137
2016-11-09 2016-09-30 13F TETRA TECH INC COM 88162G103 1,187,550 5,745 0.49 42,122 15.93 0.0131
2016-08-12 2016-06-30 13F TETRA TECH INC COM 88162G103 1,181,805 25,646 2.22 36,335 8.28 0.0118
2016-08-19 2016-03-31 13F/A-1 TETRA TECH INC COM 88162G103 1,156,159 79,105 7.34 33,556 19.74 0.0111
2016-05-13 2016-03-31 13F Tetra Tech Inc COMM 88162G103 1,156,156 34,475
2016-02-12 2015-12-31 13F Tetra Tech Inc COMM 88162G103 1,077,054 105,054 10.81 28,025 18.59 0.0093
2015-11-12 2015-09-30 13F Tetra Tech Inc COMM 88162G103 972,000 972,000 0.00 23,631 0.0079
2015-08-13 2015-06-30 13F Tetra Tech Inc COMM 88162G103 0 -923,793 -100.00 0 -100.00
2015-05-14 2015-03-31 13F Tetra Tech Inc COMM 88162G103 923,793 8,744 0.96 22,190 -9.18 0.0067
2015-02-12 2014-12-31 13F Tetra Tech Inc COM 88162G103 915,049 -31,616 -3.34 24,432 3.32 0.0074
2014-11-13 2014-09-30 13F Tetra Tech Inc COMM 88162G103 946,665 16,507 1.77 23,648 -7.55 0.0074
2014-08-14 2014-06-30 13F TETRA TECH INC com 88162G103 930,158 -124,811 -11.83 25,579 -18.06 0.0080
2014-05-14 2014-03-31 13F TETRA TECH INC COMM 88162G103 1,054,969 26,979 2.62 31,216 8.53 0.0098
2014-02-21 2013-12-31 13F/A-1 TETRA TECH INC COM 88162G103 1,027,990 -39,317 -3.68 28,763 4.09 0.0092
2014-02-12 2013-12-31 13F TETRA TECH INC COM 88162G103 1,027,990 28,763
2013-11-13 2013-09-30 13F TETRA TECH INC COM 88162G103 1,067,307 28,471 2.74 27,633 13.14 0.0097
2013-08-09 2013-06-30 13F TETRA TECH INC COM 88162G103 1,038,836 1,038,836 24,423 0.0089
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.