UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
(Amendment No. )*
Southwestern Energy Company
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(Name of Issuer)
Common Stock
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(Title of Class of Securities)
845467109
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(CUSIP Number)
December 31, 2002
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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)
[ ] Rule13d-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 9 pages
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CUSIP No. 845467109 13G Page 2 of 9 Pages
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1 NAME OF REPORTING PERSON
S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Liberty Wanger Asset Management, L.P. 36-3820584
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2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
Not Applicable (a) [ ]
(b) [ ]
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3 SEC USE ONLY
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4 CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
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5 SOLE VOTING POWER
NUMBER OF
None
SHARES ---------------------------------------------------------
SHARED VOTING POWER
BENEFICIALLY
6 1,368,500
OWNED BY ---------------------------------------------------------
SOLE DISPOSITIVE POWER
EACH
7 None
REPORTING ---------------------------------------------------------
PERSON WITH 8 SHARED DISPOSITIVE POWER
1,368,500
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9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
1,368,500
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10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
Not Applicable [ ]
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11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
5.3%
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12 TYPE OF REPORTING PERSON*
IA
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*SEE INSTRUCTION BEFORE FILLING OUT!
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CUSIP No. 845467109 13G Page 3 of 9 Pages
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1 NAME OF REPORTING PERSON
S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
WAM Acquisition GP, Inc.
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2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
Not Applicable (a) [ ]
(b) [ ]
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3 SEC USE ONLY
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4 CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
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5 SOLE VOTING POWER
NUMBER OF
None
SHARES ---------------------------------------------------------
SHARED VOTING POWER
BENEFICIALLY
6 1,368,500
OWNED BY ---------------------------------------------------------
SOLE DISPOSITIVE POWER
EACH
7 None
REPORTING ---------------------------------------------------------
PERSON WITH 8 SHARED DISPOSITIVE POWER
1,368,500
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9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
1,368,500
--------------------------------------------------------------------------------
10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
Not Applicable [ ]
--------------------------------------------------------------------------------
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
5.3%
--------------------------------------------------------------------------------
12 TYPE OF REPORTING PERSON*
CO
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*SEE INSTRUCTION BEFORE FILLING OUT!
Item 1(a) Name of Issuer:
Southwestern Energy Company
Item 1(b) Address of Issuer's Principal Executive Offices:
2350 N. Sam Houston Pkwy. E., Suite 300
Houston, TX 77032
Item 2(a) Name of Person Filing:
Liberty Wanger Asset Management, L.P.
("WAM")
WAM Acquisition GP, Inc., the general
partner of WAM ("WAM GP")
Item 2(b) Address of Principal Business Office:
WAM and WAM GP are each located at:
227 West Monroe Street, Suite 3000
Chicago, Illinois 60606
Item 2(c) Citizenship:
WAM is a Delaware limited partnership; WAM
GP is a Delaware corporation.
Item 2(d) Title of Class of Securities:
Common Stock
Item 2(e) CUSIP Number:
845467109
Item 3 Type of Person:
(e) WAM is an Investment Adviser
registered under section 203 of the
Investment Advisers Act of 1940; WAM
GP is the General Partner of the
Investment Adviser.
Page 4 of 9 pages
Item 4 Ownership (at December 31, 2002):
(a) Amount owned "beneficially" within
the meaning of rule 13d-3:
1,368,500
(b) Percent of class:
5.3% (based on 25,724,259 shares
outstanding as of October 21, 2002,
based on Form 10-Q filed on October
25, 2002).
(c) Number of shares as to which such
person has:
(i) sole power to vote or
to direct the vote:
none
(ii) shared power to vote or
to direct the vote:
1,368,500
(iii) sole power to dispose
or to direct the
disposition of: none
(iv) shared power to dispose
or to direct
disposition of:
1,368,500
Item 5 Ownership of Five Percent or Less of a Class:
Not Applicable
Item 6 Ownership of More than Five Percent on Behalf of
Another Person:
The shares reported herein have been
acquired on behalf of discretionary clients
of WAM. Persons other than WAM and WAM GP
are entitled to receive all dividends from,
and proceeds from the sale of, those shares.
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
Page 5 of 9 Pages
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 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 6 of 9 Pages
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.
Date: February 14, 2003
The undersigned corporation, on the date above
written, agrees and consents to the joint filing on
its behalf of this Schedule 13G in connection with
its beneficial ownership of the security reported
herein.
WAM Acquisition GP, Inc.
for itself and as general partner of
LIBERTY WANGER ASSET MANAGEMENT, L.P.
By: /s/ Bruce H. Lauer
--------------------------------------------
Bruce H. Lauer
Senior Vice President and Secretary
Page 7 of 9 Pages
Exhibit Index
Exhibit 1 Joint Filing Agreement dated as of February 14, 2003
by and among Liberty Wanger Asset Management, L.P.
and WAM Acquisition GP, Inc.
Page 8 of 9 Pages