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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
(Amendment No.7)*
Tetra Tech,Inc.
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(Name of Issuer)
COMMON STOCK, $0.01 par value
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(Title of Class of Securities)
881 62G 103
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(CUSIP Number)
December 31, 1999
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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:
/ / Rule 13d-1(b)
/ / Rule 13d-1(c)
/X/ 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 on 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).
POTENTIAL PERSONS WHO ARE TO RESPOND TO THE COLLECTION OF INFORMATION
CONTAINED IN THIS FORM ARE NOT REQUIRED TO RESPOND UNLESS THE FORM DISPLAYS A
CURRENTLY VALID OMB CONTROL NUMBER.
Page 1 of 5 pages
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CUSIP No. 881 62G 103
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(1) Names of Reporting Persons.
I.R.S. Identification Nos. of above persons (entities only).
Li-San Hwang
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(2) Check the Appropriate Box if a Member (a) / /
of a Group (See Instructions) (b) / /
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(3) SEC Use Only
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(4) Citizenship or Place of Organization
United States of America
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Number of Shares (5) Sole Voting Power
Beneficially 2,009,557
Owned by --------------------------------------------------
Each Reporting (6) Shared Voting Power
Person With: -0-
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(7) Sole Dispositive Power
2,009,557
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(8) Shared Dispositive Power
-0-
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(9) Aggregate Amount Beneficially Owned by Each Reporting Person
2,009,557
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(10) Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See
Instructions) / /
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(11) Percent of Class Represented by Amount in Row (11)
5.2%
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(12) Type of Reporting Person (See Instructions)
IN
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Page 2 of 5 pages
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ITEM 1.
(a) Name of Issuer
TETRA TECH, INC.
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(b) Address of Issuer's Principal Executive Offices
670 North Rosemead Boulevard
Pasadena, California 91107
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ITEM 2.
(a) Name of Person Filing
Li-San Hwang
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(b) Address of Principal Business Office or, if none, Residence
670 North Rosemead Boulevard
Pasadena, California 91107
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(c) Citizenship
United States of America
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(d) Title of Class of Securities
Common Stock, $0.01 par value
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(e) CUSIP Number
881 62G 103
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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
(15 U.S.C. 78o).
(b) / / Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).
(c) / / Insurance company as defined in section 3(a)(19) of the Act
(15 U.S.C. 78c).
(d) / / Investment company registered under section 8 of the Investment
Company Act of 1940 (15 U.S.C. 80a-8).
(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).
(h) / / A savings association as defined in section 3(b) of the Federal
Deposit Insurance Act (12 U.S.C. 1813).
(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
(15 U.S.C. 80a-3).
(j) / / Group, in accordance with section 240.13d-1(b)(1)(ii)(J).
Page 3 of 5 pages
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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:
2,009,557
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(b) Percent of class:
5.2%
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(c) Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote 2,009,557
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(ii) Shared power to vote or to direct the vote -0-
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(iii) Sole power to dispose or to direct the disposition of 2,009,557
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(iv) Shared power to dispose or to direct the disposition of -0-
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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. / /
Not Applicable
ITEM 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON
Not Applicable
ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED
THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY
Not Applicable
ITEM 8. IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP
Not Applicable
ITEM 9. NOTICE OF DISSOLUTION OF GROUP
Not Applicable
ITEM 10. CERTIFICATION
(a) The following certification shall be included if the statement is filed
pursuant to section 240.13d-1(b):
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 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.
(b) The following certification shall be included if the statement is filed
pursuant to section 240.13d-1(c):
By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above 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.
Page 4 of 5
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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 14, 2000
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Date
/s/ Li-San Hwang
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Signature
Li-San Hwang
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Name/Title
The original statement shall be signed by each person on whose behalf the
statement is filed or his authorized representative. If the statement is
signed on behalf of a person by his authorized representative other than an
executive officer or general partner of the filing person, evidence of the
representative's authority to sign on behalf of such person shall be filed
with the statement, provided, however, that a power of attorney for this
purpose which is already on file with the Commission may be incorporated by
reference. The name and any title of each person who signs the statement
shall be typed or printed beneath his signature.
NOTE: Schedules filed in paper format shall include a signed original and
five copies of the schedule, including all exhibits. See Section 240.13d-7
for other parties for whom copies are to be sent.
Attention: Intentional misstatements or omissions of fact constitute Federal
criminal violations (See 18 U.S.C. 1001)
Page 5 of 5 pages
