# EDGAR Filing Document

**Accession Number:** 0000831641
**File Stem:** 0001592089-26-000004
**Filing Date:** 2026-3
**Character Count:** 9342
**Document Hash:** c5b00049a8bba1860245ec605de227c3
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001592089-26-000004.hdr.sgml**: 20260318

**ACCESSION NUMBER**: 0001592089-26-000004

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260316

**FILED AS OF DATE**: 20260318

**DATE AS OF CHANGE**: 20260318

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Ritrievi Kimberly E
- **CENTRAL INDEX KEY:** 0001592089

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 000-19655
- **FILM NUMBER:** 26771830

**MAIL ADDRESS:**
- **STREET 1:** MATIV HOLDINGS, INC.
- **STREET 2:** 100 KIMBALL PLACE, SUITE 600
- **CITY:** ALPHARETTA
- **STATE:** GA
- **ZIP:** 30009
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** TETRA TECH INC
- **CENTRAL INDEX KEY:** 0000831641
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-ENGINEERING SERVICES [8711]
- **ORGANIZATION NAME:** 07 Trade & Services
- **EIN:** 954148514
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 0927

**BUSINESS ADDRESS:**
- **STREET 1:** 3475 EAST FOOTHILL BOULEVARD
- **CITY:** PASADENA
- **STATE:** CA
- **ZIP:** 91107
- **BUSINESS PHONE:** 6263514664

**MAIL ADDRESS:**
- **STREET 1:** 3475 EAST FOOTHILL BOULEVARD
- **CITY:** PASADENA
- **STATE:** CA
- **ZIP:** 91107

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

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[x] 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**<sup>*</sup><br>Ritrievi Kimberly E<br><sub>(Last) (First) (Middle)</sub><br>3475 EAST FOOTHILL BOULEVARD<br><sub>(Street)</sub><br>PASADENA, CA 91107<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-03-16 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [ ] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>TETRA TECH INC [ TTEK ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| COMMON STOCK | 2026-03-16 |  | M |  | 4500 | A | $0 | 149908 | D |  |
| COMMON STOCK | 2026-03-16 |  | M |  | 2250 | A | $0 | 152158 | D |  |
| COMMON STOCK | 2026-03-16 |  | M |  | 1925 | A | $0 | 154083 | D |  |
| COMMON STOCK | 2026-03-16 |  | M |  | 2910 | A | $0 | 156993 | D |  |
| COMMON STOCK | 2026-03-16 |  | M |  | 2050 | A | $0 | 159043 | D |  |
| COMMON STOCK | 2026-03-16 |  | M |  | 795 | A | $0 | 159838 | D |  |
| COMMON STOCK | 2026-03-16 |  | M |  | 795 | A | $0 | 160633 | D |  |
| COMMON STOCK | 2026-03-16 |  | M |  | 1900 | A | $0 | 162533 | D |  |
| COMMON STOCK | 2026-03-16 |  | M |  | 2125 | A | $0 | 164658 | D |  |
| COMMON STOCK | 2026-03-16 |  | M |  | 1718 | A | $0 | 166376 | D |  |
| COMMON STOCK | 2026-03-16 |  | A |  | 25883<sup>(1)</sup> | A | $0 | 192259 | D |  |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| RESTRICTED STOCK UNITS (RIGHT TO RECEIVE) | <sup>(2)</sup> | 2026-03-16 |  | M |  |  | 4500 | 2016-11-20<sup>(3)</sup> | <sup>(4)</sup> | COMMON STOCK | 4500 | $0 | 0 | D |  |
| RESTRICTED STOCK UNITS (RIGHT TO RECEIVE) | <sup>(2)</sup> | 2026-03-16 |  | M |  |  | 2250 | 2018-11-17<sup>(3)</sup> | <sup>(4)</sup> | COMMON STOCK | 2250 | $0 | 2250 | D |  |
| RESTRICTED STOCK UNITS (RIGHT TO RECEIVE) | <sup>(2)</sup> | 2026-03-16 |  | M |  |  | 1925 | 2019-11-15<sup>(3)</sup> | <sup>(4)</sup> | COMMON STOCK | 1925 | $0 | 1925 | D |  |
| RESTRICTED STOCK UNITS (RIGHT TO RECEIVE) | <sup>(2)</sup> | 2026-03-16 |  | M |  |  | 2910 | 2020-11-21<sup>(3)</sup> | <sup>(4)</sup> | COMMON STOCK | 2910 | $0 | 0 | D |  |
| RESTRICTED STOCK UNITS (RIGHT TO RECEIVE) | <sup>(2)</sup> | 2026-03-16 |  | M |  |  | 2050 | 2021-11-18<sup>(3)</sup> | <sup>(4)</sup> | COMMON STOCK | 2050<sup>(5)</sup> | $0 | 0 | D |  |
| RESTRICTED STOCK UNITS (RIGHT TO RECEIVE) | <sup>(2)</sup> | 2026-03-16 |  | M |  |  | 795 | 2022-11-18<sup>(3)</sup> | <sup>(4)</sup> | COMMON STOCK | 795<sup>(6)</sup> | $0 | 0 | D |  |
| RESTRICTED STOCK UNITS (RIGHT TO RECEIVE) | <sup>(2)</sup> | 2026-03-16 |  | M |  |  | 795 | 2022-11-18<sup>(3)</sup> | <sup>(4)</sup> | COMMON STOCK | 795<sup>(6)</sup> | $0 | 0 | D |  |
| RESTRICTED STOCK UNITS (RIGHT TO RECEIVE) | <sup>(2)</sup> | 2026-03-16 |  | M |  |  | 1900 | 2023-11-18<sup>(3)</sup> | <sup>(4)</sup> | COMMON STOCK | 1900<sup>(7)</sup> | $0 | 0 | D |  |
| RESTRICTED STOCK UNITS (RIGHT TO RECEIVE) | <sup>(2)</sup> | 2026-03-16 |  | M |  |  | 2125 | 2024-11-30<sup>(3)</sup> | <sup>(4)</sup> | COMMON STOCK | 2125<sup>(8)</sup> | $0 | 0 | D |  |
| RESTRICTED STOCK UNITS (RIGHT TO RECEIVE) | <sup>(2)</sup> | 2026-03-16 |  | M |  |  | 1718 | 2025-11-30<sup>(3)</sup> | <sup>(4)</sup> | COMMON STOCK | 1718 | $0 | 0 | D |  |

---

### Footnotes:

(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.

**Signature:** /s/ Preston Hopson, Attorney-in-fact for Kimberly E. Ritrievi  
**Date:** 2026-03-18

### Remarks:

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.**