UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
(Amendment No. )*
Mobile Mini, Inc.
(Name of Issuer)
Common Stock
(Title of Class of Securities)
60740F105
(CUSIP Number)
December 31, 2002
(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 10 pages
CUSIP No. 60740F105 13G Page 2 of 10 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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NUMBER OF 5 SOLE VOTING POWER
SHARES None
-----------------------------------------------------------------
BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY 955,000
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EACH 7 SOLE DISPOSITIVE POWER
REPORTING None
-----------------------------------------------------------------
PERSON WITH 8 SHARED DISPOSITIVE POWER
955,000
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9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
955,000
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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
6.7%
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12 TYPE OF REPORTING PERSON*
IA
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*SEE INSTRUCTION BEFORE FILLING OUT!
CUSIP No. 60740F105 13G Page 3 of 10 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) [ ]
--------------------------------------------------------------------------------
3 SEC USE ONLY
--------------------------------------------------------------------------------
4 CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
--------------------------------------------------------------------------------
NUMBER OF 5 SOLE VOTING POWER
SHARES None
-----------------------------------------------------------------
BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY 955,000
-----------------------------------------------------------------
EACH 7 SOLE DISPOSITIVE POWER
REPORTING None
-----------------------------------------------------------------
PERSON WITH 8 SHARED DISPOSITIVE POWER
955,000
--------------------------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
955,000
--------------------------------------------------------------------------------
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
6.7%
--------------------------------------------------------------------------------
12 TYPE OF REPORTING PERSON*
CO
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*SEE INSTRUCTION BEFORE FILLING OUT!
CUSIP No. 60740F105 13G Page 4 of 10 Pages
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1 NAME OF REPORTING PERSON
S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Liberty Acorn Trust
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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
--------------------------------------------------------------------------------
4 CITIZENSHIP OR PLACE OF ORGANIZATION
Massachusetts
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NUMBER OF 5 SOLE VOTING POWER
SHARES None
-----------------------------------------------------------------
BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY 825,000
-----------------------------------------------------------------
EACH 7 SOLE DISPOSITIVE POWER
REPORTING None
-----------------------------------------------------------------
PERSON WITH 8 SHARED DISPOSITIVE POWER
825,000
--------------------------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
825,000
--------------------------------------------------------------------------------
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
5.8%
--------------------------------------------------------------------------------
12 TYPE OF REPORTING PERSON*
IV
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*SEE INSTRUCTION BEFORE FILLING OUT!
Item 1(a) Name of Issuer:
Mobile Mini, Inc.
Item 1(b) Address of Issuer's Principal Executive Offices:
7420 S. Kyrene Road, Suite 101
Tempe, Arizona 85283
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")
Liberty Acorn Trust ("Acorn")
Item 2(b) Address of Principal Business Office:
WAM, WAM GP and Acorn are all 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; and Acorn is a Massachusetts business trust.
Item 2(d) Title of Class of Securities:
Common Stock
Item 2(e) CUSIP Number:
60740F105
Item 3 Type of Person:
(d) Acorn is an Investment Company under section 8 of the
Investment Company Act.
(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 5 of 10 pages
Item 4 Ownership (at December 31, 2002):
(a) Amount owned "beneficially" within the meaning of
rule 13d-3:
955,000
(b) Percent of class:
6.7% (based on 14,281,450 shares outstanding as of
November 1, 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:
955,000
(iii) sole power to dispose or to direct the
disposition of: none
(iv) shared power to dispose or to direct
disposition of: 955,000
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, including Acorn. Persons
other than WAM and WAM GP are entitled to receive all
dividends from, and proceeds from the sale of, those
shares. Acorn is the only such person known to be entitled
to all dividends from, and all proceeds from the sale of,
shares reported herein to the extent of more than 5% of the
class.
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 6 of 10 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 7 of 10 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 10, 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
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.
LIBERTY ACORN TRUST
By: /s/ Bruce H. Lauer
-------------------------------------------
Bruce H. Lauer
Vice President, Treasurer and Secretary
Page 8 of 10 pages
Exhibit Index
Exhibit 1 Joint Filing Agreement dated as of February 10, 2003 by and among
Liberty Wanger Asset Management, L.P., WAM Acquisition GP, Inc.
and Liberty Acorn Trust
Page 9 of 10 pages