SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
(Rule 13d-102)
INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
TO RULES 13d-1(b), (c) AND (d) AND AMENDMENTS THERETO FILED
PURSUANT TO 13d-2
DECEMBER 31, 2007
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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)
MONOLITHIC POWER SYSTEMS INC
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(Name of Issuer)
COMMON STOCK
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(Title of Class of Securities)
609839105
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(CUSIP Number)
CUSIP Number 609839105
1) NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
J. & W. SELIGMAN & CO. INCORPORATED
13-3043476
2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
(a) / /
(b) / x /
3) SEC USE ONLY
4) CITIZENSHIP OR PLACE OF ORGANIZATION
DELAWARE
(5) SOLE VOTING POWER -0-
NUMBER OF SHARES
BENEFICIALLY OWNED (6) SHARED VOTING POWER 2,237,400*
BY EACH REPORTING
PERSON WITH (7) SOLE DISPOSITIVE POWER -0-
(8) SHARED DISPOSITIVE POWER 2,237,400*
9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
2,237,400*
10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES / /
11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
6.80%
12) TYPE OF REPORTING PERSON
IA, CO
CUSIP Number 609839105
1) NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
WILLIAM C. MORRIS
2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
(a) / /
(b) / x /
3) SEC USE ONLY
4) CITIZENSHIP OR PLACE OF ORGANIZATION
UNITED STATES
(5) SOLE VOTING POWER -0-
NUMBER OF SHARES
BENEFICIALLY OWNED (6) SHARED VOTING POWER 2,237,400*
BY EACH REPORTING
PERSON WITH (7) SOLE DISPOSITIVE POWER -0-
(8) SHARED DISPOSITIVE POWER 2,237,400*
9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
2,237,400*
10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES / /
11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
6.80%
12) TYPE OF REPORTING PERSON
IN
* William C. Morris, as the owner of a majority of the outstanding voting
securities of J. & W. Seligman & Co. Incorporated (JWS), may be deemed to
beneficially own the shares reported herein by JWS. Accordingly, the shares
reported herein by William C. Morris include those shares separately reported
herein by JWS.
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Item 1(a) Name of Issuer:
MONOLITHIC POWER SYSTEMS INC
Item 1(b) Address of Issuer's Principal Executive Offices:
6409 GUADALUPE MINES ROAD
SAN JOSE, CA 95120
Item 2(a) Name of Person Filing:
(1) J. & W. SELIGMAN & CO. INCORPORATED (JWS)
(2) WILLIAM C. MORRIS (Mr. Morris)
Item 2(b) Address or Principal Business Office or, if none, Residence:
100 PARK AVENUE
NEW YORK, NEW YORK 10017
Item 2(c) Citizenship:
(1) DELAWARE CORPORATION
(2) UNITED STATES
Item 2(d) Title of Class of Securities:
COMMON STOCK
Item 2(e) CUSIP Number:609839105
Item 3 If this statement is filed pursuant to Rules 13d-1(b), or 13d-2(b),
check whether the person is filing as a:
JWS is an investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E).
Mr. Morris is a control person of JWS in accordance with
Rule 13d-1(b)(1)(ii)(G).
Item 4 Ownership.
Incorporated by reference to Items (5)-(9) and (11) of the cover page
pertaining to each reporting person.
Mr. Morris, as the owner of a majority of the outstanding voting
securities of JWS, may be deemed to beneficially own the shares reported herein
by JWS. Accordingly, the shares reported herein by Mr. Morris include those
shares separately reported herein by JWS.
Item 5 Ownership of Five Percent or Less of a Class.
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
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.
DATE: JANUARY 25, 2008
J. & W. SELIGMAN & CO. INCORPORATED
BY /s/ THOMAS G. ROSE
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Name: THOMAS G. ROSE
Title: CFO
/s/ Frank J. Nasta
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Frank J. Nasta, as
Attorney-in-fact for William C. Morris
EXHIBIT
7.1 Agreement of Joint Filing between J. & W. Seligman & Co.
Incorporated, William C. Morris dated JANUARY 25, 2008.
7.2 Power of Attorney for William C. Morris
EXHIBIT 7.1
AGREEMENT OF JOINT FILING
J. & W. Seligman & Co. Incorporated, William C. Morris hereby agree that the
Statement on Schedule 13G to which this agreement is attached as an exhibit,
as well as all future amendments to such Statement, shall be filed jointly on
behalf of each of them. This agreement is intended to satisfy the requirements
of Rule 13d-1(f)(1)(iii) under the Securities Exchange Act of 1934, as amended.
Dated: JANUARY 25, 2008
J. & W. SELIGMAN & CO. INCORPORATED
BY /s/ THOMAS G. ROSE
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Name: THOMAS G. ROSE
Title: CFO
/s/ Frank J. Nasta
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Frank J. Nasta, as
Attorney-in-fact for William C. Morris
EXHIBIT 7.2
POWER OF ATTORNEY FOR
WILLIAM C. MORRIS
KNOWN ALL MEN BY THESE PRESENTS, that the undersigned hereby appoints
Frank J. Nasta, attorney-in-fact and agent, with full power of substitution
and resubstitution, for in name and stead, to sign and file Forms 13D and 13G
promulgated under Section 13 of the Securities Exchange Act of 1934, as
amended, or further Amendments thereto, and any and all applications or other
documents to be filed with the Securities and Exchange Commission pertaining
thereto, with full power and authority to do and perform all acts and things
requisite and necessary to be done on the premises. This appointment shall
be valid for the sole purpose stated above and shall be in effect and force,
unless sooner revoked by me in writing.
Executed this 2nd day of February, 1998.
/s/ William C. Morris
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William C. Morris