SEC FORM 4

SEC FORM 4SEC 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

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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^*

Ritrievi Kimberly E

(Last)

(First)

(Middle)

3475 EAST FOOTHILL BOULEVARD

(Street)

PASADENA

CALIFORNIA

91107

(City)

(State)

(Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/16/2026

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

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

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

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
COMMON STOCK	03/16/2026		M		4,500	A	$0	149,908	D
COMMON STOCK	03/16/2026		M		2,250	A	$0	152,158	D
COMMON STOCK	03/16/2026		M		1,925	A	$0	154,083	D
COMMON STOCK	03/16/2026		M		2,910	A	$0	156,993	D
COMMON STOCK	03/16/2026		M		2,050	A	$0	159,043	D
COMMON STOCK	03/16/2026		M		795	A	$0	159,838	D
COMMON STOCK	03/16/2026		M		795	A	$0	160,633	D
COMMON STOCK	03/16/2026		M		1,900	A	$0	162,533	D
COMMON STOCK	03/16/2026		M		2,125	A	$0	164,658	D
COMMON STOCK	03/16/2026		M		1,718	A	$0	166,376	D
COMMON STOCK	03/16/2026		A		25,883⁽¹⁾	A	$0	192,259	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	⁽²⁾	03/16/2026		M			4,500	11/20/2016⁽³⁾	⁽⁴⁾	COMMON STOCK	4,500	$0	0	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	⁽²⁾	03/16/2026		M			2,250	11/17/2018⁽³⁾	⁽⁴⁾	COMMON STOCK	2,250	$0	2,250	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	⁽²⁾	03/16/2026		M			1,925	11/15/2019⁽³⁾	⁽⁴⁾	COMMON STOCK	1,925	$0	1,925	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	⁽²⁾	03/16/2026		M			2,910	11/21/2020⁽³⁾	⁽⁴⁾	COMMON STOCK	2,910	$0	0	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	⁽²⁾	03/16/2026		M			2,050	11/18/2021⁽³⁾	⁽⁴⁾	COMMON STOCK	2,050⁽⁵⁾	$0	0	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	⁽²⁾	03/16/2026		M			795	11/18/2022⁽³⁾	⁽⁴⁾	COMMON STOCK	795⁽⁶⁾	$0	0	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	⁽²⁾	03/16/2026		M			795	11/18/2022⁽³⁾	⁽⁴⁾	COMMON STOCK	795⁽⁶⁾	$0	0	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	⁽²⁾	03/16/2026		M			1,900	11/18/2023⁽³⁾	⁽⁴⁾	COMMON STOCK	1,900⁽⁷⁾	$0	0	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	⁽²⁾	03/16/2026		M			2,125	11/30/2024⁽³⁾	⁽⁴⁾	COMMON STOCK	2,125⁽⁸⁾	$0	0	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	⁽²⁾	03/16/2026		M			1,718	11/30/2025⁽³⁾	⁽⁴⁾	COMMON STOCK	1,718	$0	0	D

Explanation of Responses:

1. Shares acquired pursuant to vesting of performance stock units ("PSU") earned under 2018 Equity Incentive Plan. The PSUs vested between 11/23/2021 and 11/18/2025 but were deferred under the Issuer's Deferred Compensation Plan and have settled upon retirement.

2. 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.

3. The RSUs become 100% vested as to the shares underlying the RSUs on the first anniversary date.

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

5. On September 6, 2024, the balance of 410 shares was updated pursuant to a 5 to 1 forward stock split, resulting in an additional 1,640 shares of common stock.

6. On September 6, 2024, the balance of 159 shares was updated pursuant to a 5 to 1 forward stock split, resulting in an additional 636 shares of common stock.

7. On September 6, 2024, the balance of 380 shares was updated pursuant to a 5 to 1 forward stock split, resulting in an additional 1,520 shares of common stock.

8. On September 6, 2024, the balance of 425 shares was updated pursuant to a 5 to 1 forward stock split, resulting in an additional 1,700 shares of common stock.

Remarks:

	/s/ Preston Hopson, Attorney-in-fact for Kimberly E. Ritrievi	03/18/2026
	** 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.
* Form 4: SEC 1474 (03-26)

SEC Form 4 filed by Ritrievi Kimberly E