[Form 4] TETRA TECH INC Insider Trading Activity

Rhea-AI Filing Summary

Tetra Tech, Inc. (TTEK) President and officer Roger R. Argus reported multiple equity transactions involving company common stock and restricted stock units on 11/18/2025. The filing shows the exercise of restricted stock units and performance stock units into common shares, along with shares withheld to cover related tax liabilities at a price of $35.69 per share. Following these transactions, Argus directly beneficially owned 37,565 shares of Tetra Tech common stock.

The report also updates prior beneficial ownership to include 149 shares acquired on December 15, 2024 under the company’s Employee Stock Purchase Plan. The restricted stock units generally represent the right to receive one share of common stock per unit, vest in 25% annual installments beginning in November 2022 or November 2023, and become exercisable upon vesting without a set expiration date.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Argus Roger R

(Last) (First) (Middle)

3475 EAST FOOTHILL BOULEVARD

(Street)

PASADENA CA 91107

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
TETRA TECH INC [ TTEK ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President

3. Date of Earliest Transaction (Month/Day/Year)
11/18/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
COMMON STOCK	11/18/2025		M		2,055	A	$0	27,747(1)	D
COMMON STOCK	11/18/2025		M		2,535	A	$0	30,282	D
COMMON STOCK	11/18/2025		F		2,533(2)	D	$35.69	27,749	D
COMMON STOCK	11/18/2025		A		21,902(3)	A	$0	49,651	D
COMMON STOCK	11/18/2025		F		12,086(4)	D	$35.69	37,565	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	(5)	11/18/2025		M			2,055	11/18/2022(6)	(7)	COMMON STOCK	2,055	$0	0	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	(5)	11/18/2025		M			2,535	11/18/2023(8)	(7)	COMMON STOCK	2,535	$0	2,535	D

Explanation of Responses:

1. Amount of securities beneficially owned was updated to reflect that 149 shares of common stock were acquired by the Reporting Person on December 15, 2024, pursuant to the Tetra Tech, Inc. Employee Stock Purchase Plan (ESPP).

2. Represents the shares withheld to pay the related tax liability of the restricted stock units (RSUs) that vested on November 18, 2025.

3. Shares acquired pursuant to vesting of performance stock units earned under 2018 Equity Incentive Plan.

4. Represents the shares withheld to pay the related tax liability of performance stock units that vested on November 18, 2025.

5. Represents an award of restricted stock units (RSUs), each unit of which represents a contingent right to receive one share of Tetra Tech common stock.

6. The RSUs become vested as to 25% of the shares on November 18, 2022, and 25% annually, thereafter, until fully vested.

7. The RSUs are exercisable at the time of vesting and do not have a set expiration date.

8. The RSUs become vested as to 25% of the shares on November 18, 2023, and 25% annually, thereafter, until fully vested.

Remarks:

	/s/ Preston Hopson, Attorney-in-fact for Roger R. Argus	11/20/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider activity did Tetra Tech (TTEK) disclose in this Form 4?

The Form 4 reports that President Roger R. Argus exercised restricted stock units and performance stock units into Tetra Tech common stock on 11/18/2025, with some shares withheld to satisfy related tax liabilities.

How many TTEK shares does the reporting person own after these transactions?

After the reported transactions on 11/18/2025, Roger R. Argus directly beneficially owned 37,565 shares of Tetra Tech common stock.

What was the purpose of the TTEK shares withheld at $35.69?

Shares totaling 2,533 and 12,086 were reported as disposed of at $35.69 per share to cover the related tax liabilities on vested restricted stock units and performance stock units on 11/18/2025.

How were the TTEK performance stock units described in the Form 4?

The filing states that 21,902 shares were acquired upon vesting of performance stock units earned under the 2018 Equity Incentive Plan on 11/18/2025.

How do Tetra Tech (TTEK) restricted stock units vest for this insider?

The restricted stock units generally vest as to 25% of the shares on November 18, 2022 or November 18, 2023, and 25% annually thereafter until fully vested, and are exercisable at the time of vesting with no set expiration date.

What adjustment to prior TTEK share ownership was disclosed?

The report explains that the beneficially owned amount was updated to include 149 shares of common stock acquired on December 15, 2024 under the Tetra Tech, Inc. Employee Stock Purchase Plan (ESPP).