UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(AMENDMENT NO. 1)*
NUVEEN INSURED MUNICIPAL OPPORTUNITY FUND INC.
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(Name of Issuer)
Auction Rate Preferred
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(Title of Class of Securities)
670984-30-1
(See Item 2(e))
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(CUSIP Number)
December 31, 2009
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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)
/ / 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 9 Pages
SCHEDULE 13G
CUSIP NO. 670984-30-1 Page 2 of 9 Pages
(See Item 2(e))
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(1) NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
Citigroup Global Markets Inc.
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(2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a) / /
(b) / /
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(3) SEC USE ONLY
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(4) CITIZENSHIP OR PLACE OF ORGANIZATION New York
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NUMBER OF (5) SOLE VOTING POWER 0
SHARES
----------------------------------------------------
BENEFICIALLY (6) SHARED VOTING POWER 1,891
OWNED BY
----------------------------------------------------
EACH (7) SOLE DISPOSITIVE POWER 0
REPORTING
----------------------------------------------------
PERSON (8) SHARED DISPOSITIVE POWER 1,891
WITH:
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(9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,891
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(10) CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
INSTRUCTIONS) / /
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(11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 6.9%
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(12) TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) BD
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SCHEDULE 13G
CUSIP NO. 670984-30-1 Page 3 of 9 Pages
(See Item 2(e))
-------------------------------------------------------------------------------
(1) NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
Citigroup Financial Products Inc.
-------------------------------------------------------------------------------
(2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(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 0
SHARES
----------------------------------------------------
BENEFICIALLY (6) SHARED VOTING POWER 1,891
OWNED BY
----------------------------------------------------
EACH (7) SOLE DISPOSITIVE POWER 0
REPORTING
----------------------------------------------------
PERSON (8) SHARED DISPOSITIVE POWER 1,891
WITH:
-------------------------------------------------------------------------------
(9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,891
-------------------------------------------------------------------------------
(10) CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
INSTRUCTIONS) / /
-------------------------------------------------------------------------------
(11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 6.9%
-------------------------------------------------------------------------------
(12) TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) CO
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SCHEDULE 13G
CUSIP NO. 670984-30-1 Page 4 of 9 Pages
(See Item 2(e))
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(1) NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
Citigroup Global Markets Holdings Inc.
-------------------------------------------------------------------------------
(2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a) / /
(b) / /
-------------------------------------------------------------------------------
(3) SEC USE ONLY
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(4) CITIZENSHIP OR PLACE OF ORGANIZATION New York
-------------------------------------------------------------------------------
NUMBER OF (5) SOLE VOTING POWER 0
SHARES
----------------------------------------------------
BENEFICIALLY (6) SHARED VOTING POWER 1,891
OWNED BY
----------------------------------------------------
EACH (7) SOLE DISPOSITIVE POWER 0
REPORTING
----------------------------------------------------
PERSON (8) SHARED DISPOSITIVE POWER 1,891
WITH:
-------------------------------------------------------------------------------
(9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,891
-------------------------------------------------------------------------------
(10) CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
INSTRUCTIONS) / /
-------------------------------------------------------------------------------
(11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 6.9%
-------------------------------------------------------------------------------
(12) TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) HC
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SCHEDULE 13G
CUSIP NO. 670984-30-1 Page 5 of 9 Pages
(See Item 2(e))
-------------------------------------------------------------------------------
(1) NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
Citigroup Inc.
-------------------------------------------------------------------------------
(2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a) / /
(b) / /
-------------------------------------------------------------------------------
(3) SEC USE ONLY
-------------------------------------------------------------------------------
(4) CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
-------------------------------------------------------------------------------
NUMBER OF (5) SOLE VOTING POWER 0
SHARES
----------------------------------------------------
BENEFICIALLY (6) SHARED VOTING POWER 1,891*
OWNED BY
----------------------------------------------------
EACH (7) SOLE DISPOSITIVE POWER 0
REPORTING
----------------------------------------------------
PERSON (8) SHARED DISPOSITIVE POWER 1,891*
WITH:
-------------------------------------------------------------------------------
(9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,891*
-------------------------------------------------------------------------------
(10) CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
INSTRUCTIONS) / /
-------------------------------------------------------------------------------
(11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 6.9%*
-------------------------------------------------------------------------------
(12) TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) HC
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* Includes shares held by the other reporting persons.
Item 1(a). Name of Issuer:
NUVEEN INSURED MUNICIPAL OPPORTUNITY FUND INC.
Item 1(b). Address of Issuer's Principal Executive Offices:
333 West Wacker Drive
Chicago, IL 60606
Item 2(a). Name of Person Filing:
Citigroup Global Markets Inc. ("CGM")
Citigroup Financial Products Inc. ("CFP")
Citigroup Global Markets Holdings Inc. ("CGM Holdings")
Citigroup Inc. ("Citigroup")
Item 2(b). Address of Principal Office or, if none, Residence:
The address of the principal office of each of
CGM, CFP and CGM Holdings is:
388 Greenwich Street
New York, NY 10013
The address of the principal office of Citigroup is:
399 Park Avenue
New York, NY 10043
Item 2(c). Citizenship or Place of Organization:
CGM and CGM Holdings are New York corporations.
CFP and Citigroup are Delaware corporations.
Item 2(d). Title of Class of Securities:
Auction Rate Preferred
Item 2(e). CUSIP Number:
670984-20-2
670984-30-1
670984-40-0
670984-50-9
670984-60-8
670984-70-7
670984-80-6
Page 6
of 9 Pages
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(n):
(a) [X] 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) [ ] Investment adviser in accordance with Section
240.13d-1(b)(1)(ii)(E);
(f) [ ] Employee benefit plan or endowment fund in accordance
with Section 240.13d-1(b)(1)(ii)(F);
(g) [X] Parent holding company or control person in accordance
with Section 240.13d-1(b)(1)(ii)(G);
(h) [ ] Savings association as defined in Section 3(b) of the
Federal Deposit Insurance Act (12 U.S.C. 1813);
(i) [ ] 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) [ ] A non-U.S. institution in accordance with Section
240.13d-1(b)(1)(ii)(J);
(k) [ ] Group, in accordance with Section 240.13d-1(b)(1)(ii)(K).
If filing as a non-U.S. institution in accordance with
Section 240.13d-1(b)(1)(ii)(J), please specify the type
of institution: ____________________________ .
Item 4. Ownership. (as of December 31, 2009)
The number of shares reported herein represents combined holdings
in multiple series of auction rate preferred securities of the issuer,
which are treated herein as one class of securities in accordance
with the Securities and Exchange Commission's Auction Rate
Securities -- Global Exemptive Relief no-action letter issued on
September 22, 2008.
(a) Amount beneficially owned: See item 9 of cover pages
(b) Percent of class: See item 11 of cover pages
(c) Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
(ii) Shared power to vote or to direct the vote:
(iii) Sole power to dispose or to direct the disposition of:
(iv) Shared power to dispose or to direct the disposition of:
See Items 5-8 of cover pages
Page 7
of 9 Pages
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 [ ].
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.
CFP is the sole stockholder of CGM. CGM Holdings is the sole
stockholder of CFP. Citigroup is the sole stockholder of
CGM Holdings.
Item 8. Identification and Classification of Members of the Group.
Not Applicable.
Item 9. Notice of Dissolution of Group.
Not Applicable.
Page 8
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.
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.
Dated: February 3, 2010
CITIGROUP GLOBAL MARKETS INC.
By: /s/ Ali L. Karshan
--------------------------------------------
Name: Ali L. Karshan
Title: Assistant Secretary
CITIGROUP FINANCIAL PRODUCTS INC.
By: /s/ Ali L. Karshan
--------------------------------------------
Name: Ali L. Karshan
Title: Assistant Secretary
CITIGROUP GLOBAL MARKETS HOLDINGS INC.
By: /s/ Ali L. Karshan
--------------------------------------------
Name: Ali L. Karshan
Title: Assistant Secretary
CITIGROUP INC.
By: /s/ Ali L. Karshan
--------------------------------------------
Name: Ali L. Karshan
Title: Assistant Secretary
Page 9
of 9 Pages
EXHIBIT INDEX TO SCHEDULE 13G
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EXHIBIT 1
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Agreement among CGM, CFP, CGM Holdings and Citigroup as to joint filing of
Schedule 13G