United States
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
(Amendment No. 1)*
Name of Issuer - Tencor Instruments, Inc.
Title or Class of Securities - Common Stock
CUSIP Number - 880323100
Check the following box if a fee is being paid with this statement [ ].
<PAGE>
Cusip No. 880323100
Page 2 of 10 Pages
1. Name of Reporting Person (S.S. or I.R.S. Identification No. of above
person)
American Century Companies, Inc. - 43-1325032 (formerly known as Twentieth
Century Companies, Inc.)
2. Check the appropriate box if a member of a group* - N/A
3. SEC Use Only
4. Citizenship or place of organization
Delaware
5. Sole voting power
N/A
6. Shared voting power
N/A
7. Sole dispositive power
N/A
8. Shared dispositive power
N/A
9. Aggregate amount beneficially owned by each reporting person
N/A
10. Check box if the aggregate amount in Row (9) excludes certain shares -
N/A
11. Percent of class represented by amount in Row 9
N/A
12. Type of reporting person*
HC
<PAGE>
Cusip No. 880323100
Page 3 of 10 Pages
1. Name of Reporting Person (S.S. or I.R.S. Identification No. of above
person)
American Century Investment Management - 44-0640487 (formerly known as
Investors Research Corporation)
2. Check the appropriate box if a member of a group* - N/A
3. SEC Use Only
4. Citizenship or place of organization
Delaware
5. Sole voting power
N/A
6. Shared voting power
N/A
7. Sole dispositive power
N/A
8. Shared dispositive power
N/A
9. Aggregate amount beneficially owned by each reporting person
N/A
10. Check box if the aggregate amount in Row (9) excludes certain shares
N/A
11. Percent of class represented by amount in Row 9
N/A
12. Type of reporting person*
IA
<PAGE>
Cusip No. 880323100
Page 4 of 10 Pages
1. Name of Reporting Person (S.S. or I.R.S. Identification No. of above
person)
American Century Mutual Funds, Inc. - 44-6006315 (formerly known as
Twentieth Century Investors, Inc.)
2. Check the appropriate box if a member of a group* - N/A
3. SEC Use Only
4. Citizenship or place of organization
Maryland
5. Sole voting power
N/A
6. Shared voting power
N/A
7. Sole dispositive power
N/A
8. Shared dispositive power
N/A
9. Aggregate amount beneficially owned by each reporting person
N/A
10. Check box if the aggregate amount in Row (9) excludes certain shares
N/A
11. Percent of class represented by amount in Row 9
N/A
12. Type of reporting person*
IV
<PAGE>
Cusip No. 880323100
Page 5 of 10 Pages
1. Name of Reporting Person (S.S. or I.R.S. Identification No. of above
person)
James E. Stowers, Jr. - ###-##-####
2. Check the appropriate box if a member of a group* - N/A
3. SEC Use Only
4. Citizenship or place of organization
United States
5. Sole voting power
N/A
6. Shared voting power
N/A
7. Sole dispositive power
N/A
8. Shared dispositive power
N/A
9. Aggregate amount beneficially owned by each reporting person
N/A
10. Check box if the aggregate amount in Row (9) excludes certain shares
N/A
11. Percent of class represented by amount in Row 9
N/A
12. Type of reporting person*
IN
<PAGE>
SCHEDULE 13G
Item 1(a). NAME OF ISSUER
Tencor Instruments, Inc.
Item 1(b). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES
2400 Charleston Road
Mountain View, CA 94043
Item 2(a). NAME OF PERSONS FILING
American Century Companies, Inc., on its behalf and on behalf of:
American Century Investment Management, Inc.
American Century Mutual Funds, Inc.
James E. Stowers, Jr.
Item 2(b). ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE
4500 Main Street, P.O. Box 418210, Kansas City, MO 64141-9210
Attn: David H. Reinmiller
Item 2(c). CITIZENSHIP
Delaware
Item 2(d). TITLE OF CLASS OF SECURITIES
Common Stock
Item 2(e). CUSIP NO.
880323100
Item 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13d-
1(b) OR 13d-2(b), CHECK WHETHER THE PERSON FILING IS A
(g) [ X ] Parent Holding Company, in accordance with
Rule 13d-1(b)(ii)(G) (Note: See Item 7).
Item 4. OWNERSHIP
(a) Aggregate amount beneficially owned:
N/A
(b) Percent of class:
N/A
(c) Number of shares as to which such person has:
(i) sole power to vote or to direct the vote:
N/A
(ii) shared power to vote or to direct the vote:
N/A
(iii)sole power to dispose or to direct the disposition of:
N/A
(iv) shared power to dispose or to direct the disposition of:
N/A
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 [X].
Item 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF
ANOTHER PERSON
American Century Investment Management, Inc. (formerly Investors Research
Corporation), a registered investment adviser and a wholly-owned subsidiary of
American Century Companies, Inc. (formerly Twentieth Century Companies, Inc.),
manages, pursuant to management agreements, the investments of six registered
investment companies, American Century Mutual Funds, Inc., American Century
World Mutual Funds, Inc., American Century Capital Portfolios, Inc., American
Century Premium Reserves, Inc., TCI Portfolios, Inc., and American Century
Strategic Asset Allocations, Inc. It also manages the assets of institutional
investor accounts. The securities that are the subject of this report are owned
by and held for such investment companies and separate institutional investor
accounts. Any dividends received from such securities, or the proceeds of any
sale of such securities, are for the benefit of, and are held for such
investment companies and separate institutional investor accounts.
For further information regarding the ownership of the securities that are
the subject of this report, see Exhibit A attached hereto.
Item 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE
SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY
See attached Exhibits A and B.
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 in the ordinary course of
business and were not acquired for the purpose of and do not have the effect of
changing or influencing the control of the issuer of such securities and were
not acquired in connection with or as a participant in any transaction having
such 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 7, 1997 AMERICAN CENTURY COMPANIES, INC.
Date
By: /s/ William M. Lyons
William M. Lyons
Executive Vice President
<PAGE>
EXHIBIT A
IDENTITY AND ITEM 3 CLASSIFICATION OF A SUBSIDIARY OF
PARENT HOLDING COMPANIES
This Schedule 13G is being filed by American Century Companies, Inc.
("ACC"). American Century Investment Management, Inc. ("ACIM"), an investment
advisor registered under Section 203 of the Investment Advisors Act of 1940, is
a wholly-owned subsidiary of ACC. Mr. James E. Stowers, Jr., controls ACC by
virtue of his beneficial ownership of a majority of the voting stock of ACC.
As a result of its status as investment advisor to six investment companies
registered under Section 8 of the Investment Company Act and to several
institutional investors, ACIM is deemed to be the beneficial owner of and has
the sole authority to dispose of and vote certain shares (the "Shares") of the
outstanding common stock of Tencor Instruments, Inc. (the "Issuer").
ACC, as a result of its control of ACIM, and Mr. Stowers, as a result of
his control of ACC, are also deemed to beneficially own all such shares deemed
to be beneficially owned by ACIM. Mr. Stowers, ACC and ACIM all disclaim
beneficial ownership of the Shares.
The ownership of one investment company client of ACIM, American Century
Mutual Funds, Inc. ("ACMF"), formerly totalled more than 5% of a class of
securities of the Issuer.
This Schedule 13G is being filed by ACC on behalf of ACC, ACIM, ACMF and
Mr. Stowers.
<PAGE>
EXHIBIT B
Rule 13d-1(f)(1)(iii) Agreement
Each of the undersigned hereby agrees and consents to the execution and
joint filing on its or his behalf by American Century Companies, Inc. of this
Schedule 13G respecting the beneficial ownership of the common stock of Tencor
Instruments, Inc. at December 31, 1996.
Dated this 7th day of February, 1997.
American Century Companies, Inc.
By: /s/ William M. Lyons
William M. Lyons
Executive Vice President
American Century Investment Management, Inc.
By: /s/ William M. Lyons
William M. Lyons
Executive Vice President
American Century Mutual Funds, Inc.
By: /s/ William M. Lyons
William M. Lyons
Executive Vice President
James E. Stowers, Jr.
By: /s/ William M. Lyons, Attorney-in-fact
William M. Lyons
Under Power of Attorney dated 2/3/97
on file with Schedule 13G for
U.S. Robotics, Inc. filed 2/3/97
