0000831641 2026-08-04 2026-08-04 0000831641 1 2026-08-04 2026-08-04 iso4217:USD pure shares S-8 S-8 EX-FILING FEES 0000831641 TETRA TECH INC N/A false S-8 TETRA TECH INC Equity Common stock par value $0.01 per share true 10000000 28.80 288000000.00 0.0001381 39772.80 288000000.00 39772.80 0.00 39772.80 Pursuant to Rule 416 under the Securities Act of 1933, as amended (the "Securities Act"), this Registration Statement shall also cover any additional shares of common stock, par value $0.01 per share ("Common Stock"), of Tetra Tech, Inc. ("Tetra Tech") that may become issuable in respect of the securities identified in the above table to prevent dilution as a result of any stock dividend, stock split, recapitalization or other similar transaction. The "Proposed Maximum Offering Price Per Unit" and the "Maximum Aggregate Offering Price" are estimated solely for the purpose of determining the registration fee pursuant to Rule 457(c) and 457(h) under the Securities Act, and are based on a price of $28.80 per share, which price is a 15% discount from the average of the high and low prices of Tetra Tech's Common Stock as reported on the Nasdaq Global Select Market on August 3, 2026, such discount representing the maximum permissible discount offered pursuant to the Tetra Tech Amended Employee Stock Purchase Plan, as amended and restated (the "ESPP"). The "Amount Registered" represents 10,000,000 shares of Common Stock reserved for issuance under the ESPP.