SCHEDULE 13G
(RULE 13d-102)
Information to be Included in Statements Filed Pursuant to Rule 13d-1(b), (c)
and (d) and Amendments Thereto Filed Pursuant to Rule 13d-2.
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, DC 20549
Under the Securities Exchange Act of 1934
(Amendment No. 4)*
TETRA TECH, INC.
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(Name of Issuer)
Common Stock
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(Title of Class of Securities)
88162G 10 3
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(CUSIP Number)
December 31, 2001
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(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:
[X] Rule 13d-1(b)
[ ] Rule 13d-1(c)
[ ] Rule 13d-1(d)
*The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class of
securities, and for any subsequent amendment containing information which would
alter the disclosures provided in a prior cover page.
The information required in the remainder of this cover page shall not
be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 ("Act") or otherwise subject to the liabilities of that section of
the Act, but shall be subject to all other provisions of the Act (however, see
the Notes).
Page 1 of 6 pages
13G
CUSIP NO. 88162G 10 3 AMENDMENT NO. 4 PAGE 2 OF 6 PAGES
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1 Names of Reporting Persons/I.R.S. Identification Nos. of Above Persons
(Entities Only)
The Northwestern Mutual Life Insurance Company
39-0509570
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2 Check the Appropriate Box if a Member of a Group (a) [ ]
(See Instructions) (b) [ ]
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3 SEC Use Only
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4 Citizenship or Place of Organization
Wisconsin
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Number of
5 Sole Voting Power
Shares 1,009,993
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Beneficially 6 Shared Voting Power
1,867,056
Owned by -----------------------------------------------------
7 Sole Dispositive Power
Each 1,009,993
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Reporting 8 Shared Dispositive Power
1,867,056
Person With
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9 Aggregate Amount Beneficially Owned by Each Reporting Person
2,877,049
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10 Check if the Aggregate Amount in Row (9) Excludes Certain Shares [ ]
(See Instructions)
N/A
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11 Percent of Class Represented by Amount in Row (9)
5.5%
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12 Type of Reporting Person (See Instructions)
IC
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CUSIP NO. 88162G 10 3 13G Page 3 of 6 Pages
AMENDMENT NO. 4
ITEM 1
(a) Name of Issuer: Tetra Tech, Inc.
(b) Address of Issuer's Principal Executive Offices:
670 North Rosemead Boulevard, Pasadena, CA 91107
ITEM 2
(a) Name of Person Filing: The Northwestern Mutual
Life Insurance Company
(b) Address of Principal Business Office: 720 East
Wisconsin Avenue, Milwaukee, Wisconsin 53202
(c) Citizenship or Place of Organization: Wisconsin
(d) Title of Class of Securities: Common Stock
(e) CUSIP Number: 88162G 10 3
ITEM 3 IF THIS STATEMENT IS FILED PURSUANT TO SECTIONS
240.13d-1(b), OR 240.13d-2(b) OR (c), CHECK
WHETHER THE PERSON FILING IS A:
(a) / / Broker or Dealer registered under Section 15
of the Act
(b) / / Bank as defined in section 3(a)(6) of the Act
(c) /X/ Insurance company as defined in section
3(a)(19) of the Act
(d) / / Investment company registered under section 8
of the Investment Company Act of 1940
(e) / / An investment adviser in accordance with
section 240.13d-1(b)(1)(ii)(E)
(f) / / An employee benefit plan or endowment fund in
accordance with section 240.13d-1(b)(1)(ii)(F)
(g) / / A parent holding company or control person in
accordance with section 240.13d-1(b)(1)(ii)(G)
CUSIP NO. 88162G 10 3 13G Page 4 of 6 Pages
AMENDMENT NO. 4
(h) / / A savings association as defined in
Section 3(b) of the Federal Deposit Insurance Act
(i) / / A church plan that is excluded from the
definition of an investment company under
section 3(c)(14) of the Investment Company Act
of 1940
(j) / / Group, in accordance with section
240.13d-1(b)(1)(ii)(J)
ITEM 4 OWNERSHIP
Provide the following information regarding the aggregate number and
percentage of the class of securities of the issuer identified in Item 1.
(a) Amount Beneficially Owned: 2,877,049 shares. Of such amount, (i)
6,750 shares are owned by the Asset Allocation Portfolio, 1,256,347 shares are
owned by the Growth Stock Portfolio and 297,625 shares are owned by the Small
Cap Aggressive Growth Stock Portfolio of Northwestern Mutual Series Fund, Inc.,
an affiliate of The Northwestern Mutual Life Insurance Company and a registered
investment company; (ii) 273,116 shares are owned by The Northwestern Mutual
Life Insurance Company Group Annuity Separate Account; (iii) 12,000 shares are
owned by the Asset Allocation Fund and 14,750 shares are owned by the Small Cap
Growth Stock Fund of Mason Street Funds, Inc., an affiliate of The Northwestern
Mutual Life Insurance Company and a registered investment company; and (iv)
6,468 shares are owned by Northwestern Long Term Care Insurance Company, a
wholly owned subsidiary of The Northwestern Mutual Life Insurance Company. As of
December 31, 2001, Northwestern Mutual Investment Services, LLC, a wholly owned
company of The Northwestern Mutual Life Insurance Company and a registered
investment advisor, served as an investment advisor to the Asset Allocation
Portfolio, Growth Stock Portfolio and Small Cap Aggressive Growth Stock
Portfolio of Northwestern Mutual Series Fund, Inc., Asset Allocation Fund and
Small Cap Growth Stock Fund of Mason Street Funds, Inc., and Northwestern Long
Term Care Insurance Company. As of December 31, 2001, Northwestern Investment
Management Company, LLC, of which The Northwestern Mutual Life
CUSIP NO. 88162G 10 3 13G Page 5 of 6 Pages
AMENDMENT NO. 4
Insurance Company is the sole member, served as an investment advisor to The
Northwestern Mutual Life Insurance Company.
(b) Percent of Class: 5.5%
(c) Number of shares as to which such person has:
(i) Sole power to vote or to direct the vote:
1,009,993
(ii) Shared power to vote or to direct the
vote: 1,867,056
(iii) Sole power to dispose or to direct the
disposition of: 1,009,993
(iv) Shared power to dispose or to direct the
disposition of: 1,867,056
ITEM 5 OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS
If this statement is being filed to report the fact that as of the date
hereof the reporting person has ceased to be the beneficial owner of more than
five percent of the class of securities, check the following / /.
ITEM 6 OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF
ANOTHER PERSON: N/A
ITEM 7 IDENTIFICATION AND CLASSIFICATION OF THE
SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING
REPORTED ON BY THE PARENT HOLDING COMPANY OR
CONTROL PERSON: N/A
ITEM 8 IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF
THE GROUP: N/A
ITEM 9 NOTICE OF DISSOLUTION OF GROUP: N/A
ITEM 10 CERTIFICATION
By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were acquired and are held in the
ordinary course of business and
CUSIP NO. 88162G 10 3 13G Page 6 of 6 Pages
AMENDMENT NO. 4
were not acquired and are not held for the purpose of or with the effect of
changing or influencing the control of the issuer of the securities and were not
acquired and are not held in connection with or as a participant in any
transaction having that purpose or effect.
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.
February 1, 2002
THE NORTHWESTERN MUTUAL LIFE
INSURANCE COMPANY
By: /s/ Robert J. Berdan
Robert J. Berdan
Vice President, General
Counsel and Secretary