Form N-Q

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549

FORM N-Q


QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF REGISTERED MANAGEMENT INVESTMENT COMPANY

Investment Company Act file number         811-06379         

        Nuveen Insured Municipal Opportunity Fund, Inc.         
(Exact name of registrant as specified in charter)

Nuveen Investments
        333 West Wacker Drive, Chicago, Illinois 60606         

(Address of principal executive offices) (Zip code)


Kevin J. McCarthy Vice President and Secretary
        333 West Wacker Drive, Chicago, Illinois 60606         

(Name and address of agent for service)

Registrant's telephone number, including area code:         312-917-7700        

Date of fiscal year end:            10/31          

Date of reporting period:         7/31/09         

Form N-Q is to be used by management investment companies, other than small business investment companies registered on Form N-5 (§§ 239.24 and 274.5 of this chapter), to file reports with the Commission, not later than 60 days after the close of the first and third fiscal quarters, pursuant to rule 30b1-5 under the Investment Company Act of 1940 (17 CFR 270.30b1-5). The Commission may use the information provided on Form N-Q in its regulatory, disclosure review, inspection, and policymaking roles.

A registrant is required to disclose the information specified by Form N-Q, and the Commission will make this information public. A registrant is not required to respond to the collection of information contained in Form N-Q unless the Form displays a currently valid Office of Management and Budget ("OMB") control number. Please direct comments concerning the accuracy of the information collection burden estimate and any suggestions for reducing the burden to the Secretary, Securities and Exchange Commission, 450 Fifth Street, NW, Washington, DC 20549-0609. The OMB has reviewed this collection of information under the clearance requirements of 44 U.S.C. § 3507.

Item 1. Schedule of Investments

  Portfolio of Investments (Unaudited)       
  Nuveen Insured Municipal Opportunity Fund, Inc. (NIO)       
July 31, 2009
 
 
 
Principal    Optional Call     
Amount (000)  Description (1)  Provisions (2)  Ratings (3)  Value 
  Alabama – 6.3% (4.0% of Total Investments)       
$          10,500  Birmingham Waterworks And Sewer Board, Alabama, Water and Sewer Revenue Bonds, 4.500%,  1/17 at 100.00  Aa1  $     9,277,065 
   1/01/43 – AMBAC Insured (UB)       
11,175  Hoover Board of Education, Alabama, Capital Outlay Tax Anticipation Warrants, Series 2001,  2/11 at 100.00  AA–  11,541,764 
   5.250%, 2/15/22 – MBIA Insured       
2,500  Jefferson County, Alabama, Sewer Revenue Capital Improvement Warrants, Series 2002B, 5.125%,  8/12 at 100.00  AAA  2,735,950 
   2/01/42 (Pre-refunded 8/01/12) – FGIC Insured       
  Jefferson County, Alabama, Sewer Revenue Capital Improvement Warrants, Series 2002D:       
425   5.000%, 2/01/38 (Pre-refunded 8/01/12) – FGIC Insured  8/12 at 100.00  AAA  458,401 
14,800   5.000%, 2/01/42 (Pre-refunded 8/01/12) – FGIC Insured  8/12 at 100.00  AAA  16,143,100 
18,760  Jefferson County, Alabama, Sewer Revenue Capitol Improvement Warrants, Series 2001A, 5.000%,  2/11 at 101.00  AAA  19,773,040 
   2/01/41 (Pre-refunded 2/01/11) – FGIC Insured       
10,195  Jefferson County, Alabama, Sewer Revenue Refunding Warrants, Series 1997A, 5.375%, 2/01/27 –  8/10 at 100.00  Caa3  3,531,752 
   FGIC Insured       
5,240  Jefferson County, Alabama, Sewer Revenue Refunding Warrants, Series 2003B, 5.000%, 2/01/41  2/11 at 101.00  AAA  5,558,382 
   (Pre-refunded 2/01/11) – FGIC Insured       
73,595  Total Alabama      69,019,454 
  Alaska – 0.6% (0.4% of Total Investments)       
2,425  Alaska Housing Finance Corporation, Collateralized Veterans Mortgage Program Bonds, First  12/09 at 100.00  AAA  2,430,602 
   Series 1999A-1, 6.150%, 6/01/39       
3,745  Alaska Housing Finance Corporation, General Mortgage Revenue Bonds, Series 1999A, 6.050%,  12/09 at 100.00  AAA  3,746,685 
   6/01/39 – MBIA Insured       
6,170  Total Alaska      6,177,287 
  Arizona – 2.3% (1.5% of Total Investments)       
  Arizona State University, Certificates of Participation, Resh Infrastructure Projects,       
  Series 2005A:       
2,000   5.000%, 9/01/25 – AMBAC Insured  3/15 at 100.00  AA–  2,021,260 
2,000   5.000%, 9/01/27 – AMBAC Insured  3/15 at 100.00  AA–  2,004,740 
1,000  Arizona State University, System Revenue Bonds, Series 2005, 5.000%, 7/01/27 – AMBAC Insured  7/15 at 100.00  N/R  1,028,300 
1,000  Maricopa County Union High School District 210, Phoenix, Arizona, General Obligation Bonds,  7/14 at 100.00  AAA  1,155,780 
   Series 2004A, 5.000%, 7/01/22 (Pre-refunded 7/01/14) – FSA Insured       
5,200  Mesa, Arizona, Utility System Revenue Bonds, Reset Option Longs, Series 11032– 11034, 13.143%,  7/17 at 100.00  AAA  3,224,104 
   7/01/31 – FSA Insured (IF)       
1,150  Phoenix Civic Improvement Corporation, Arizona, Junior Lien Wastewater System Revenue Bonds,  7/14 at 100.00  AA+  1,172,023 
   Series 2004, 5.000%, 7/01/27 – MBIA Insured       
13,490  Phoenix Civic Improvement Corporation, Arizona, Junior Lien Water System Revenue Bonds, Series  7/15 at 100.00  AAA  13,743,747 
   2005, 4.750%, 7/01/25 – MBIA Insured       
1,350  Pima County Industrial Development Authority, Arizona, Lease Obligation Revenue Refunding  1/10 at 100.00  Aa3  1,357,250 
   Bonds, Tucson Electric Power Company, Series 1988A, 7.250%, 7/15/10 – FSA Insured       
27,190  Total Arizona      25,707,204 
  Arkansas – 0.2% (0.1% of Total Investments)       
2,660  Arkansas State University, Student Fee Revenue Bonds, Beebe Campus, Series 2006, 5.000%,  9/15 at 100.00  N/R  2,591,798 
   9/01/35 – AMBAC Insured       
  California – 30.8% (19.4% of Total Investments)       
5,600  Alameda Corridor Transportation Authority, California, Subordinate Lien Revenue Bonds, Series  No Opt. Call  A–  2,517,312 
   2004A, 0.000%, 10/01/20 – AMBAC Insured       
10,000  California Department of Veterans Affairs, Home Purchase Revenue Bonds, Series 2002A, 5.300%,  6/12 at 101.00  Aa2  10,268,900 
   12/01/21 – AMBAC Insured       
  California Department of Water Resources, Power Supply Revenue Bonds, Series 2002A:       
30,000   5.375%, 5/01/17 (Pre-refunded 5/01/12) – SYNCORA GTY Insured  5/12 at 101.00  Aaa  34,001,998 
20,000   5.375%, 5/01/18 (Pre-refunded 5/01/12) – AMBAC Insured  5/12 at 101.00  Aaa  22,668,000 
  California Department of Water Resources, Water System Revenue Bonds, Central Valley Project,       
  Series 2005AC:       
30   5.000%, 12/01/24 (Pre-refunded 12/01/14) – MBIA Insured  12/14 at 100.00  AAA  35,174 
25   5.000%, 12/01/27 (Pre-refunded 12/01/14) – MBIA Insured  12/14 at 100.00  AAA  29,312 
  California Department of Water Resources, Water System Revenue Bonds, Central Valley Project,       
  Series 2005AC:       
3,670   5.000%, 12/01/24 – NPFG Insured (UB)  12/14 at 100.00  AAA  3,844,876 
2,795   5.000%, 12/01/27 – MBIA Insured (UB)  12/14 at 100.00  AAA  2,891,232 
10,150  California, General Obligation Bonds, Series 2004, 5.000%, 6/01/31 – AMBAC Insured  12/14 at 100.00  9,594,998 
3,500  Coachella Valley Unified School District, Riverside County, California, General Obligation  8/15 at 100.00  3,503,605 
   Bonds, Series 2005A, 5.000%, 8/01/26 – FGIC Insured       
20,000  Cucamonga County Water District, San Bernardino County, California, Certificates of  9/11 at 101.00  AA–  18,472,600 
   Participation, Water Shares Purchase, Series 2000, 5.125%, 9/01/35 – FGIC Insured       
5,750  East Bay Municipal Utility District, Alameda and Contra Costa Counties, California, Water  6/15 at 100.00  AAA  5,922,500 
   System Subordinated Revenue Bonds, Series 2005A, 5.000%, 6/01/27 – MBIA Insured       
10,000  Golden State Tobacco Securitization Corporation, California, Tobacco Settlement Asset-Backed  6/15 at 100.00  A–  8,257,800 
   Revenue Bonds, Series 2005A, 5.000%, 6/01/38 – FGIC Insured       
1,520  Hayward Redevelopment Agency, California, Downtown Redevelopment Project Tax Allocation Bonds,  3/16 at 100.00  A–  1,198,003 
   Series 2006, 5.000%, 3/01/36 – SYNCORA GTY Insured       
5,600  Kern Community College District, California, General Obligation Bonds, Series 2006, 0.000%,  No Opt. Call  AAA  2,233,280 
   11/01/24 – FSA Insured       
5,000  Long Beach Bond Financing Authority, California, Lease Revenue Refunding Bonds, Long Beach  11/11 at 101.00  BBB  4,259,400 
   Aquarium of the South Pacific, Series 2001, 5.250%, 11/01/30 – AMBAC Insured       
2,740  Los Angeles Harbors Department, California, Revenue Bonds, Series 2006A, 5.000%, 8/01/22 –  8/16 at 102.00  AA  2,703,174 
   FGIC Insured (Alternative Minimum Tax)       
20,000  Los Angeles Unified School District, California, General Obligation Bonds, Series 2003A,  7/13 at 100.00  AAA  20,488,200 
   5.000%, 7/01/21 – FSA Insured       
3,000  Los Angeles Unified School District, California, General Obligation Bonds, Series 2006F,  7/16 at 100.00  AA–  3,010,320 
   5.000%, 7/01/24 – FGIC Insured       
5,200  Palomar Pomerado Health General Obligation Bonds, Election of 2004, California, Series 2009A,  8/29 at 100.00  AAA  2,995,460 
   0.000%, 8/01/38 – AGC Insured       
6,205  Port of Oakland, California, Revenue Bonds, Series 2002L, 5.000%, 11/01/22 – FGIC Insured  11/12 at 100.00  A1  5,604,294 
   (Alternative Minimum Tax)       
  Poway Redevelopment Agency, California, Tax Allocation Bonds, Paguay Redevelopment Project,       
  Series 2001:       
15,000   5.200%, 6/15/30 – AMBAC Insured  12/11 at 101.00  N/R  12,712,500 
5,000   5.125%, 6/15/33 – AMBAC Insured  12/11 at 101.00  N/R  4,032,600 
2,035  Redding, California, Electric System Revenue Certificates of Participation, Series 2005,  6/15 at 100.00  AA–  1,751,341 
   5.000%, 6/01/30 – FGIC Insured       
6,000  Redlands Unified School District, San Bernardino County, California, General Obligation Bonds,  7/13 at 100.00  AAA  6,050,640 
   Series 2003, 5.000%, 7/01/26 – FSA Insured       
2,970  Riverside Community College District, California, General Obligation Bonds, Series 2005,  8/15 at 100.00  AAA  3,083,692 
   5.000%, 8/01/22 – FSA Insured       
2,500  Sacramento County Sanitation District Financing Authority, California, Revenue Bonds, Series  12/15 at 100.00  AA  2,565,000 
   2005B, 4.750%, 12/01/21 – FGIC Insured       
13,710  San Francisco Airports Commission, California, Revenue Refunding Bonds, San Francisco  5/11 at 100.00  A1  12,949,643 
   International Airport, Second Series 2001, Issue 27A, 5.250%, 5/01/26 – MBIA Insured       
   (Alternative Minimum Tax)       
3,030  San Francisco Bay Area Rapid Transit District, California, Sales Tax Revenue Bonds, Series  7/11 at 100.00  AA+  3,031,788 
   2001, 5.125%, 7/01/36 – AMBAC Insured       
8,470  San Francisco Bay Area Rapid Transit District, California, Sales Tax Revenue Bonds, Series  7/11 at 100.00  AA+ (4)  9,203,502 
   2001, 5.125%, 7/01/36 (Pre-refunded 7/01/11) – AMBAC Insured       
1,220  San Francisco Bay Area Rapid Transit District, California, Sales Tax Revenue Bonds, Series  7/15 at 100.00  AA+  1,266,092 
   2005A, 5.000%, 7/01/22 – MBIA Insured       
66,685  San Joaquin Hills Transportation Corridor Agency, Orange County, California, Senior Lien Toll  No Opt. Call  AAA  41,815,491 
   Road Revenue Bonds, Series 1993, 0.000%, 1/01/21 (ETM)       
  San Joaquin Hills Transportation Corridor Agency, Orange County, California, Toll Road Revenue       
  Refunding Bonds, Series 1997A:       
31,615   5.250%, 1/15/30 – NPFG Insured  1/10 at 100.00  21,373,953 
21,500   0.000%, 1/15/32 – NPFG Insured  No Opt. Call  3,662,740 
12,525  San Jose Redevelopment Agency, California, Tax Allocation Bonds, Merged Area Redevelopment  8/10 at 101.00  A (4)  13,220,388 
   Project, Series 2002, 5.000%, 8/01/20 (Pre-refunded 8/01/10) – MBIA Insured       
19,595  San Jose Redevelopment Agency, California, Tax Allocation Bonds, Merged Area Redevelopment  8/17 at 100.00  13,944,782 
   Project, Series 2006C, 4.250%, 8/01/30 – MBIA Insured       
11,250  Santa Ana Financing Authority, California, Lease Revenue Bonds, Police Administration and  No Opt. Call  AA–  12,266,325 
   Housing Facility, Series 1994A, 6.250%, 7/01/24 – MBIA Insured       
6,785  Santa Clara Valley Water District, California, Water Revenue Bonds, Series 2006A, 3.750%,  6/16 at 100.00  AAA  5,902,950 
   6/01/25 – FSA Insured       
5,000  Walnut Energy Center Authority, California, Electric Revenue Bonds, Turlock Irrigation  1/14 at 100.00  A+  4,798,950 
   District, Series 2004A, 5.000%, 1/01/34 – AMBAC Insured       
405,675  Total California      338,132,815 
  Colorado – 7.1% (4.5% of Total Investments)       
1,080  Arkansas River Power Authority, Colorado, Power Revenue Bonds, Series 2006, 5.250%, 10/01/40 –  10/16 at 100.00  BBB  847,811 
   SYNCORA GTY Insured       
1,900  Aspen, Colorado, Sales Tax Revenue Bonds, Parks and Open Space, Series 2005B, 5.250%,  11/15 at 100.00  AAA  2,026,065 
   11/01/24 – FSA Insured       
1,000  Colorado Department of Transportation, Certificates of Participation, Series 2004, 5.000%,  6/14 at 100.00  AA–  1,034,650 
   6/15/25 – MBIA Insured       
4,950  Denver Convention Center Hotel Authority, Colorado, Senior Revenue Bonds, Convention Center  12/13 at 100.00  N/R (4)  5,552,613 
   Hotel, Series 2003A, 5.000%, 12/01/33 (Pre-refunded 12/01/13) – SYNCORA GTY Insured       
1,740  Douglas County School District RE1, Douglas and Elbert Counties, Colorado, General Obligation  12/14 at 100.00  Aa2  1,774,365 
   Bonds, Series 2005B, 5.000%, 12/15/28 – FSA Insured       
35,995  E-470 Public Highway Authority, Colorado, Senior Revenue Bonds, Series 1997B, 0.000%,  No Opt. Call  13,529,801 
   9/01/23 – NPFG Insured       
30,800  E-470 Public Highway Authority, Colorado, Senior Revenue Bonds, Series 2000A, 5.750%, 9/01/35  9/10 at 102.00  AAA  33,155,274 
   (Pre-refunded 9/01/10) – MBIA Insured       
11,800  E-470 Public Highway Authority, Colorado, Senior Revenue Bonds, Series 2000B, 0.000%, 9/01/15  9/10 at 74.80  Aaa  8,723,386 
   (Pre-refunded 9/01/10) – NPFG Insured       
10,000  E-470 Public Highway Authority, Colorado, Toll Revenue Bonds, Series 2004A, 0.000%, 9/01/27 –  No Opt. Call  2,721,900 
   NPFG Insured       
4,520  Jefferson County School District R1, Colorado, General Obligation Bonds, Series 2004, 5.000%,  12/14 at 100.00  AAA  4,657,001 
   12/15/24 – FSA Insured (UB)       
2,500  Summit County School District RE-1, Summit, Colorado, General Obligation Bonds, Series 2004B,  12/14 at 100.00  Aa3  2,619,125 
   5.000%, 12/01/24 – FGIC Insured       
1,000  University of Colorado, Enterprise System Revenue Bonds, Series 2005, 5.000%, 6/01/30 –  6/15 at 100.00  AA–  1,014,070 
   FGIC Insured       
107,285  Total Colorado      77,656,061 
  District of Columbia – 1.1% (0.7% of Total Investments)       
  District of Columbia Water and Sewerage Authority, Subordinate Lien Public Utility Revenue       
  Bonds, Series 2003:       
5,000   5.125%, 10/01/24 – FGIC Insured  10/13 at 100.00  AA–  5,102,000 
5,000   5.125%, 10/01/25 – FGIC Insured  10/13 at 100.00  AA–  5,079,250 
2,670  Washington Convention Center Authority, District of Columbia, Senior Lien Dedicated Tax  10/16 at 100.00  AAA  2,281,889 
   Revenue Bonds, Series 2007, Residuals 1606, 11.216%, 10/01/30 – AMBAC Insured (IF)       
12,670  Total District of Columbia      12,463,139 
  Florida – 6.3% (4.0% of Total Investments)       
1,000  Hillsborough County School Board, Florida, Certificates of Participation, Master Lease  7/15 at 100.00  AA–  1,002,500 
   Program, Series 2005A, 5.000%, 7/01/26 – MBIA Insured       
  Indian Trace Development District, Florida, Water Management Special Benefit Assessment Bonds,       
  Series 2005:       
645   5.000%, 5/01/25 – MBIA Insured  5/15 at 102.00  Baa1  553,287 
1,830   5.000%, 5/01/27 – MBIA Insured  5/15 at 102.00  Baa1  1,522,944 
4,425  Jacksonville Economic Development Commission, Florida, Healthcare Facilities Revenue Bonds,  11/12 at 100.00  Aa2  4,462,967 
   Mayo Clinic, Series 2001C, 5.500%, 11/15/36 – MBIA Insured       
1,505  Lee County, Florida, Transportation Facilities Revenue Bonds, Series 2004B, 5.000%, 10/01/21 –  10/14 at 100.00  A–  1,557,479 
   AMBAC Insured       
2,000  Marco Island, Florida, Water Utility System Revenue Bonds, Series 2003, 5.000%, 10/01/27 –  10/13 at 100.00  1,992,780 
   MBIA Insured       
2,150  Miami-Dade County, Florida, Aviation Revenue Bonds, Miami International Airport, Series 2002A,  10/12 at 100.00  AAA  1,866,931 
   5.125%, 10/01/35 – FSA Insured (Alternative Minimum Tax)       
35,920  Miami-Dade County, Florida, Aviation Revenue Bonds, Miami International Airport, Series 2002,  10/12 at 100.00  31,936,111 
   5.375%, 10/01/32 – FGIC Insured (Alternative Minimum Tax)       
12,930  Miami-Dade County, Florida, Public Facilities Revenue Bonds, Jackson Health System, Series  12/15 at 100.00  A1  10,935,677 
   2005A, 5.000%, 6/01/32 – MBIA Insured       
5,320  Miami-Dade County, Florida, Public Facilities Revenue Bonds, Jackson Health System, Series  6/15 at 100.00  A1  4,805,875 
   2005B, 5.000%, 6/01/25 – MBIA Insured       
  Northern Palm Beach County Improvement District, Florida, Revenue Bonds, Water Control and       
  Improvement Development Unit 9B, Series 2005:       
1,290   5.000%, 8/01/23 – MBIA Insured  8/15 at 102.00  1,317,284 
2,145   5.000%, 8/01/29 – MBIA Insured  8/15 at 102.00  AA–  2,089,445 
2,320  Osceola County, Florida, Transportation Revenue Bonds, Osceola Parkway, Series 2004, 5.000%,  4/14 at 100.00  A3  2,344,151 
   4/01/23 – MBIA Insured       
2,225  Plantation, Florida, Non-Ad Valorem Revenue Refunding and Improvement Bonds, Series 2003,  8/13 at 100.00  Aa3  2,283,963 
   5.000%, 8/15/18 – FSA Insured       
75,705  Total Florida      68,671,394 
  Georgia – 1.0% (0.7% of Total Investments)       
1,000  Atlanta, Georgia, Water and Wastewater Revenue Bonds, Series 2004, 5.000%, 11/01/22 –  11/14 at 100.00  AAA  1,014,210 
   FSA Insured       
1,520  College Park Business and Industrial Development Authority, Georgia, Revenue Bonds, Public  9/14 at 102.00  AA–  1,591,242 
   Safety Project, Series 2004, 5.250%, 9/01/23 – MBIA Insured       
  Fulton County Development Authority, Georgia, Revenue Bonds, Georgia Tech Molecular Science       
  Building, Series 2004:       
1,695   5.250%, 5/01/19 – MBIA Insured  5/14 at 100.00  Aa3  1,852,381 
1,135   5.250%, 5/01/20 – MBIA Insured  5/14 at 100.00  Aa3  1,229,534 
4,500   5.000%, 5/01/36 – MBIA Insured  5/14 at 100.00  Aa3  4,486,500 
1,250  Glynn-Brunswick Memorial Hospital Authority, Georgia, Revenue Bonds, Southeast Georgia Health  10/09 at 100.00  AA  1,251,775 
   Systems, Series 1996, 5.250%, 8/01/13 – MBIA Insured       
11,100  Total Georgia      11,425,642 
  Idaho – 0.2% (0.2% of Total Investments)       
170  Idaho Housing Agency, Single Family Mortgage Senior Bonds, Series 1994B-1, 6.750%, 7/01/22  No Opt. Call  Aa1  178,247 
135  Idaho Housing Agency, Single Family Mortgage Senior Bonds, Series 1994B-2, 6.900%, 7/01/26  No Opt. Call  Aa1  139,919 
   (Alternative Minimum Tax)       
180  Idaho Housing Agency, Single Family Mortgage Senior Bonds, Series 1995B, 6.600%, 7/01/27  1/10 at 100.00  Aaa  185,992 
   (Alternative Minimum Tax)       
  Idaho Housing and Finance Association, Grant and Revenue Anticipation Bonds, Federal Highway       
  Trust Funds, Series 2006:       
1,000   5.000%, 7/15/23 – MBIA Insured  7/16 at 100.00  Aa3  1,041,920 
1,065   5.000%, 7/15/24 – MBIA Insured  7/16 at 100.00  Aa3  1,106,077 
2,550  Total Idaho      2,652,155 
  Illinois – 6.0% (3.7% of Total Investments)       
1,050  Bedford Park, Illinois, General Obligation Bonds, Series 2004A, 5.250%, 12/15/20 – FSA Insured  12/14 at 100.00  AAA  1,116,224 
  Chicago, Illinois, Second Lien Passenger Facility Charge Revenue Refunding Bonds, O’Hare       
  International Airport, Series 2001E:       
4,615   5.500%, 1/01/17 – AMBAC Insured (Alternative Minimum Tax)  1/11 at 101.00  A1  4,646,890 
4,870   5.500%, 1/01/18 – AMBAC Insured (Alternative Minimum Tax)  1/11 at 101.00  A1  4,881,737 
7,200  Chicago, Illinois, Third Lien General Airport Revenue Bonds, O’Hare International Airport,  1/16 at 100.00  A1  7,333,056 
   Series 2005A, 5.250%, 1/01/24 – MBIA Insured       
10,000  Illinois Development Finance Authority, Revenue Bonds, Provena Health, Series 1998A, 5.500%,  11/09 at 100.50  9,665,900 
   5/15/21 – MBIA Insured       
2,095  Illinois Educational Facilities Authority, Revenue Bonds, Robert Morris College, Series 2000,  12/09 at 100.00  Baa1  2,095,461 
   5.800%, 6/01/30 – MBIA Insured       
22,510  Illinois, General Obligation Bonds, Illinois FIRST Program, Series 2002, 5.125%, 2/01/27 –  2/12 at 100.00  AA–  22,851,927 
   FGIC Insured       
20,045  Metropolitan Pier and Exposition Authority, Illinois, Revenue Bonds, McCormick Place Expansion  No Opt. Call  AAA  4,005,793 
   Project, Series 2002A, 0.000%, 12/15/35 – MBIA Insured       
  Schaumburg, Illinois, General Obligation Bonds, Series 2004B:       
4,260   5.000%, 12/01/22 – FGIC Insured  12/14 at 100.00  AA+  4,476,110 
2,365   5.000%, 12/01/23 – FGIC Insured  12/14 at 100.00  AA+  2,478,851 
4,000  Southwestern Illinois Development Authority, School Revenue Bonds, Triad School District 2,  No Opt. Call  A+  1,689,720 
   Madison County, Illinois, Series 2006, 0.000%, 10/01/25 – NPFG Insured       
83,010  Total Illinois      65,241,669 
  Indiana – 3.9% (2.4% of Total Investments)       
2,030  Decatur Township-Marion County Multi-School Building Corporation, Indiana, First Mortgage  7/13 at 100.00  AA+ (4)  2,302,609 
   Bonds, Series 2003, 5.000%, 7/15/20 (Pre-refunded 7/15/13) – FGIC Insured       
8,000  Indiana Municipal Power Agency, Power Supply Revenue Bonds, Series 2007A, 5.000%, 1/01/42 –  1/17 at 100.00  A+  7,606,160 
   MBIA Insured       
20,000  Indianapolis Local Public Improvement Bond Bank, Indiana, Series 1999E, 0.000%, 2/01/28 –  No Opt. Call  AA  7,530,800 
   AMBAC Insured       
3,250  Indianapolis Local Public Improvement Bond Bank, Indiana, Waterworks Project, Series 2002A,  7/12 at 100.00  AAA  3,646,533 
   5.250%, 7/01/33 (Pre-refunded 7/01/12) – MBIA Insured       
1,340  Monroe-Gregg Grade School Building Corporation, Morgan County, Indiana, First Mortgage Bonds,  1/14 at 100.00  AAA  1,532,129 
   Series 2004, 5.000%, 1/15/25 (Pre-refunded 1/15/14) – FSA Insured       
5,000  Noblesville Redevelopment Authority, Indiana, Economic Development Lease Rental Bonds, Exit 10  7/13 at 100.00  AA–  5,030,150 
   Project, Series 2003, 5.000%, 1/15/28 – AMBAC Insured       
10,000  Purdue University, Indiana, Student Fee Bonds, Series 2002O, 5.000%, 7/01/19 – MBIA Insured  1/12 at 100.00  Aa1  10,349,100 
3,705  Whitley County Middle School Building Corporation, Columbia City, Indiana, First Mortgage  7/13 at 100.00  Aa3 (4)  4,231,703 
   Bonds, Series 2003, 5.000%, 7/15/16 (Pre-refunded 7/15/13) – FSA Insured       
53,325  Total Indiana      42,229,184 
  Kansas – 1.3% (0.8% of Total Investments)       
2,055  Kansas Turnpike Authority, Revenue Bonds, Series 2004A-2, 5.000%, 9/01/23 – FSA Insured  9/14 at 101.00  AAA  2,195,747 
  Neosho County Unified School District 413, Kansas, General Obligation Bonds, Series 2006:       
2,145   5.000%, 9/01/27 – FSA Insured  9/14 at 100.00  Aa3  2,248,754 
4,835   5.000%, 9/01/29 – FSA Insured  9/14 at 100.00  Aa3  5,025,934 
5,000  University of Kansas Hospital Authority, Health Facilities Revenue Bonds, KU Health System,  9/09 at 100.00  AAA  5,020,250 
   Series 1999A, 5.650%, 9/01/29 (Pre-refunded 9/01/09) – AMBAC Insured       
14,035  Total Kansas      14,490,685 
  Kentucky – 3.7% (2.3% of Total Investments)       
3,870  Kenton County School District Finance Corporation, Kentucky, School Building Revenue Bonds,  6/14 at 100.00  Aa3  4,039,390 
   Series 2004, 5.000%, 6/01/20 – MBIA Insured       
  Kentucky State Property and Buildings Commission, Revenue Bonds, Project 93, Refunding       
  Series 2009:       
3,860   5.250%, 2/01/20 – AGC Insured  2/19 at 100.00  AAA  4,329,994 
10,000   5.250%, 2/01/24 – AGC Insured  2/19 at 100.00  AAA  10,789,600 
7,500  Kentucky Turnpike Authority, Economic Development Road Revenue Bonds, Revitalization Project,  7/16 at 100.00  AA+  7,868,175 
   Series 2006B, 5.000%, 7/01/25 – AMBAC Insured       
12,980  Louisville and Jefferson County Metropolitan Sewer District, Kentucky, Sewer and Drainage  11/11 at 101.00  AA–  13,158,735 
   System Revenue Bonds, Series 2001A, 5.500%, 5/15/34 – MBIA Insured       
38,210  Total Kentucky      40,185,894 
  Louisiana – 5.9% (3.7% of Total Investments)       
5,000  DeSoto Parish, Louisiana, Pollution Control Revenue Refunding Bonds, Cleco Utility Group Inc.  9/09 at 102.00  Baa1  4,716,050 
   Project, Series 1999, 5.875%, 9/01/29 – AMBAC Insured       
3,025  Lafayette City and Parish, Louisiana, Utilities Revenue Bonds, Series 2004, 5.250%, 11/01/22 –  11/14 at 100.00  A1  3,156,830 
   MBIA Insured       
4,545  Louisiana Public Facilities Authority, Revenue Bonds, Baton Rouge General Hospital, Series  7/14 at 100.00  4,611,584 
   2004, 5.250%, 7/01/24 – MBIA Insured       
  Louisiana State, Gasoline and Fuels Tax Revenue Bonds, Series 2005A:       
2,400   5.000%, 5/01/25 – FGIC Insured  5/15 at 100.00  AA  2,489,208 
4,415   5.000%, 5/01/26 – FGIC Insured  5/15 at 100.00  AA  4,557,031 
5,000   5.000%, 5/01/27 – FGIC Insured  5/15 at 100.00  AA  5,135,250 
  Louisiana State, Gasoline and Fuels Tax Revenue Bonds, Series 2006:       
3,300   4.750%, 5/01/39 – FSA Insured (UB)  5/16 at 100.00  AAA  3,227,730 
35,725   4.500%, 5/01/41 – FGIC Insured (UB)  5/16 at 100.00  Aa2  32,229,309 
38  Louisiana State, Gasoline Tax Revenue Bonds, Series 2006, Residuals 660-1, 13.832%, 5/01/41 –  5/16 at 100.00  AA  23,333 
   FGIC Insured (IF)       
4,950  Orleans Levee District, Louisiana, Levee District General Obligation Bonds, Series 1986,  12/09 at 100.00  AAA  4,963,266 
   5.950%, 11/01/15 – FSA Insured       
68,398  Total Louisiana      65,109,591 
  Maine – 0.3% (0.2% of Total Investments)       
3,000  Maine Health and Higher Educational Facilities Authority, Revenue Bonds, Series 2003B, 5.000%,  7/13 at 100.00  AAA  3,360,840 
   7/01/28 (Pre-refunded 7/01/13) – FSA Insured       
  Maryland – 0.3% (0.2% of Total Investments)       
5,345  Baltimore, Maryland, Senior Lien Convention Center Hotel Revenue Bonds, Series 2006A, 5.250%,  9/16 at 100.00  Baa3  3,806,495 
   9/01/28 – SYNCORA GTY Insured       
  Massachusetts – 5.7% (3.6% of Total Investments)       
22,500  Massachusetts Development Finance Authority, Revenue Bonds, WGBH Educational Foundation,  1/12 at 101.00  N/R (4)  25,049,700 
   Series 2002A, 5.375%, 1/01/42 (Pre-refunded 1/01/12) – AMBAC Insured       
11,000  Massachusetts School Building Authority, Dedicated Sales Tax Revenue Bonds, Series 2005A,  8/15 at 100.00  AAA  11,847,550 
   5.000%, 8/15/23 – FSA Insured (UB)       
7,255  Massachusetts Water Resources Authority, General Revenue Bonds, 4.500%, 8/01/46 –  2/17 at 100.00  AAA  6,373,010 
   FSA Insured (UB)       
15,000  Massachusetts, Special Obligation Dedicated Tax Revenue Bonds, Series 2004, 5.250%, 1/01/23  1/14 at 100.00  A (4)  17,013,300 
   (Pre-refunded 1/01/14) – FGIC Insured       
1,500  University of Massachusetts Building Authority, Senior Lien Project Revenue Bonds, Series  11/14 at 100.00  A+ (4)  1,764,570 
   2004-1, 5.375%, 11/01/20 (Pre-refunded 11/01/14) – AMBAC Insured       
57,255  Total Massachusetts      62,048,130 
  Michigan – 6.7% (4.2% of Total Investments)       
5,490  Detroit City School District, Wayne County, Michigan, Unlimited Tax School Building and Site  No Opt. Call  AAA  5,508,337 
   Improvement Bonds, Series 2001A, 6.000%, 5/01/29 – FSA Insured (UB)       
6,000  Detroit, Michigan, General Obligation Bonds, Series 2001A-1, 5.375%, 4/01/18 – MBIA Insured  10/11 at 100.00  5,633,100 
7,420  Detroit, Michigan, Senior Lien Water Supply System Revenue Bonds, Series 1997A, 5.000%,  1/10 at 100.00  A+  6,698,479 
   7/01/27 – MBIA Insured       
  Detroit, Michigan, Sewerage Disposal System Revenue Bonds, Series 1999A:       
15,825   5.750%, 7/01/26 (Pre-refunded 1/01/10) – FGIC Insured  1/10 at 101.00  Aaa  16,327,919 
20,000   5.875%, 7/01/27 (Pre-refunded 1/01/10) – FGIC Insured  1/10 at 101.00  Aaa  20,646,000 
1,085  Grand Rapids Community College, Kent County, Michigan, General Obligation Refunding Bonds,  5/13 at 100.00  AA  1,167,731 
   Series 2003, 5.250%, 5/01/20 – AMBAC Insured       
6,850  Wayne County, Michigan, Airport Revenue Bonds, Detroit Metropolitan Wayne County Airport,  12/09 at 100.50  6,853,357 
   Series 1998A, 5.375%, 12/01/15 – MBIA Insured (Alternative Minimum Tax)       
10,000  Wayne County, Michigan, Limited Tax General Obligation Airport Hotel Revenue Bonds, Detroit  12/11 at 101.00  10,069,100 
   Metropolitan Wayne County Airport, Series 2001A, 5.250%, 12/01/25 – MBIA Insured       
72,670  Total Michigan      72,904,023 
  Minnesota – 2.3% (1.4% of Total Investments)       
5,000  City of Minneapolis, Minnesota, Health Care System Revenue Bonds, Fairview Health Services,  11/18 at 100.00  AAA  5,462,000 
   Series 2008B, 6.500%, 11/15/38 – AGC Insured       
4,000  Northern Municipal Power Agency, Minnesota, Electric System Revenue Bonds, Refunding Series  No Opt. Call  AAA  4,378,280 
   2009A, 5.000%, 1/01/15 – AGC Insured       
13,020  Saint Paul Housing and Redevelopment Authority, Minnesota, Multifamily Housing Revenue Bonds,  12/11 at 102.00  Aaa  14,997,087 
   Marian Center Project, Series 2001A, 6.450%, 6/20/43 (Pre-refunded 12/20/11)       
22,020  Total Minnesota      24,837,367 
  Nebraska – 2.8% (1.8% of Total Investments)       
27,125  Lincoln, Nebraska, Electric System Revenue Bonds, Series 2007A, 4.500%, 9/01/37 –  9/17 at 100.00  AA  24,652,014 
   FGIC Insured (UB)       
5,000  Municipal Energy Agency of Nebraska, Power Supply System Revenue and Refunding Bonds, Series  4/19 at 100.00  AAA  5,219,950 
   2009A, 5.375%, 4/01/39 – BHAC Insured       
1,000  Nebraska Public Power District, General Revenue Bonds, Series 2005A, 5.000%, 1/01/25 –  1/15 at 100.00  AAA  1,027,630 
   FSA Insured       
33,125  Total Nebraska      30,899,594 
  Nevada – 7.1% (4.5% of Total Investments)       
8,475  Clark County, Nevada, General Obligation Bank Bonds, Southern Nevada Water Authority Loan,  12/12 at 100.00  AA+  8,129,135 
   Series 2002, 5.000%, 6/01/32 – MBIA Insured       
3,630  Clark County, Nevada, General Obligation Bank Bonds, Southern Nevada Water Authority Loan,  12/12 at 100.00  AA+ (4)  4,102,880 
   Series 2002, 5.000%, 6/01/32 (Pre-refunded 12/01/12) – MBIA Insured       
7,370  Clark County, Nevada, Subordinate Lien Airport Revenue Bonds, Series 2004A-2, 5.125%,  7/14 at 100.00  Aa3  7,454,165 
   7/01/25 – FGIC Insured       
  Director of Nevada State Department of Business and Industry, Revenue Bonds, Las Vegas       
  Monorail Project, First Tier, Series 2000:       
15,000   5.625%, 1/01/34 – AMBAC Insured  1/10 at 102.00  Caa2  3,008,100 
13,000   5.375%, 1/01/40 – AMBAC Insured  1/10 at 100.00  Caa2  2,607,280 
14,985  Reno, Nevada, Capital Improvement Revenue Bonds, Series 2002, 5.375%, 6/01/32 – FGIC Insured  6/12 at 100.00  12,833,753 
25,300  Reno, Nevada, Capital Improvement Revenue Bonds, Series 2002, 5.375%, 6/01/32 (Pre-refunded  6/12 at 100.00  Baa1 (4)  28,334,986 
   6/01/12) – FGIC Insured       
10,000  Reno, Nevada, Senior Lien Sales and Room Tax Revenue Bonds, Reno Transportation Rail Access  6/12 at 100.00  Baa3 (4)  11,141,900 
   Corridor Project, Series 2002, 5.125%, 6/01/27 (Pre-refunded 6/01/12) – AMBAC Insured       
97,760  Total Nevada      77,612,199 
  New Jersey – 2.4% (1.5% of Total Investments)       
  Essex County Improvement Authority, New Jersey, Guaranteed Revenue Bonds, Project       
  Consolidation, Series 2004:       
2,000   5.125%, 10/01/21 – MBIA Insured  10/14 at 100.00  A1  2,081,040 
2,250   5.125%, 10/01/22 – MBIA Insured  10/14 at 100.00  A1  2,328,930 
  New Jersey Economic Development Authority, Revenue Bonds, Motor Vehicle Surcharge,       
  Series 2004A:       
3,850   5.000%, 7/01/22 – MBIA Insured  7/14 at 100.00  3,919,454 
3,850   5.000%, 7/01/23 – MBIA Insured  7/14 at 100.00  3,911,831 
8,250  New Jersey Turnpike Authority, Revenue Bonds, Series 2003A, 5.000%, 1/01/19 – FGIC Insured  7/13 at 100.00  A+  8,837,565 
3,320  New Jersey Turnpike Authority, Revenue Bonds, Series 2005A, 5.000%, 1/01/21 – FSA Insured (UB)  1/15 at 100.00  AAA  3,543,436 
2,000  New Jersey Turnpike Authority, Revenue Bonds, Series 2003A, 5.000%, 1/01/23 – FSA Insured (UB)  7/13 at 100.00  AAA  2,074,720 
25,520  Total New Jersey      26,696,976 
  New Mexico – 1.6% (1.0% of Total Investments)       
3,660  San Juan County, New Mexico, Subordinate Gross Receipts Tax Revenue Bonds, Series 2005,  6/15 at 100.00  A+  3,717,462 
   5.000%, 6/15/25 – MBIA Insured       
13,600  University of New Mexico, System Improvement Subordinated Lien Revenue Bonds, Series 2007A,  6/17 at 100.00  AAA  13,460,328 
   5.000%, 6/01/36 – FSA Insured       
17,260  Total New Mexico      17,177,790 
  New York – 7.0% (4.4% of Total Investments)       
1,880  Dormitory Authority of the State of New York, FHA-Insured Mortgage Revenue Bonds, Montefiore  2/15 at 100.00  1,899,796 
   Hospital, Series 2004, 5.000%, 8/01/23 – FGIC Insured       
3,335  Dormitory Authority of the State of New York, State Personal Income Tax Revenue Bonds, Series  3/15 at 100.00  AAA  3,478,405 
   2005F, 5.000%, 3/15/24 – AMBAC Insured       
3,820  Hudson Yards Infrastructure Corporation, New York, Revenue Bonds, Series 2006A, 4.500%,  2/17 at 100.00  3,049,735 
   2/15/47 – MBIA Insured       
12,500  Long Island Power Authority, New York, Electric System General Revenue Bonds, Series 2006A,  6/16 at 100.00  12,643,375 
   5.000%, 12/01/25 – FGIC Insured       
6,900  Long Island Power Authority, New York, Electric System Revenue Bonds, Series 2006F, 4.250%,  11/16 at 100.00  5,641,854 
   5/01/33 – MBIA Insured       
  Metropolitan Transportation Authority, New York, State Service Contract Refunding Bonds,       
  Series 2002A:       
1,500   5.000%, 7/01/21 – FGIC Insured  7/12 at 100.00  AA–  1,521,255 
5,000   5.000%, 7/01/25 – FGIC Insured  7/12 at 100.00  AA–  5,029,400 
2,615  New York City Industrial Development Agency, New York, Revenue Bonds, Yankee Stadium Project  3/19 at 100.00  AAA  2,948,674 
   Pilot, Series 2009A, 7.000%, 3/01/49 – AGC Insured       
5,000  New York City, New York, General Obligation Bonds, Fiscal Series 2005F-1, 5.000%, 9/01/21 –  9/15 at 100.00  AA  5,209,850 
   AMBAC Insured       
10,000  New York City, New York, General Obligation Bonds, Fiscal Series 2005M, 5.000%, 4/01/26 –  4/15 at 100.00  AA  10,162,000 
   FGIC Insured       
5,000  New York State Thruway Authority, General Revenue Bonds, Series 2005F, 5.000%, 1/01/26 –  1/15 at 100.00  A+  5,082,750 
   AMBAC Insured       
  New York State Urban Development Corporation, State Personal Income Tax Revenue Bonds,       
  Series 2004A-1:       
1,000   5.000%, 3/15/23 – FGIC Insured  3/14 at 100.00  AAA  1,041,090 
5,000   5.000%, 3/15/25 – FGIC Insured  3/14 at 100.00  AAA  5,163,700 
3,650  New York State Urban Development Corporation, State Personal Income Tax Revenue Bonds, Series  3/15 at 100.00  AAA  3,792,496 
   2005B, 5.000%, 3/15/25 – FSA Insured (UB)       
10,000  Triborough Bridge and Tunnel Authority, New York, Subordinate Lien General Purpose Revenue  11/12 at 100.00  Aa3  10,038,300 
   Refunding Bonds, Series 2002E, 5.000%, 11/15/32 – MBIA Insured       
77,200  Total New York      76,702,680 
  North Carolina – 1.5% (1.0% of Total Investments)       
  Mooresville, North Carolina, Enterprise System Revenue Bonds, Series 2004:       
2,115   5.000%, 5/01/22 – FGIC Insured  5/14 at 100.00  2,118,384 
2,575   5.000%, 5/01/26 – FGIC Insured  5/14 at 100.00  2,598,639 
5,000  North Carolina Municipal Power Agency 1, Catawba Electric Revenue Bonds, Series 2003A, 5.250%,  1/13 at 100.00  AAA  5,344,150 
   1/01/16 – FSA Insured       
  Raleigh Durham Airport Authority, North Carolina, Airport Revenue Bonds, Series 2005A:       
3,205   5.000%, 5/01/23 – AMBAC Insured  5/15 at 100.00  Aa3  3,252,722 
3,295   5.000%, 5/01/24 – AMBAC Insured  5/15 at 100.00  Aa3  3,337,440 
16,190  Total North Carolina      16,651,335 
  North Dakota – 0.6% (0.4% of Total Investments)       
  Grand Forks, North Dakota, Sales Tax Revenue Bonds, Alerus Project, Series 2005A:       
2,195   5.000%, 12/15/22 – MBIA Insured  12/15 at 100.00  A1  2,283,459 
1,355   5.000%, 12/15/23 – MBIA Insured  12/15 at 100.00  A1  1,402,046 
3,000   5.000%, 12/15/24 – MBIA Insured  12/15 at 100.00  A1  3,095,730 
6,550  Total North Dakota      6,781,235 
  Ohio – 4.3% (2.7% of Total Investments)       
2,650  Cleveland State University, Ohio, General Receipts Bonds, Series 2004, 5.250%, 6/01/24 –  6/14 at 100.00  2,657,632 
   FGIC Insured       
2,000  Columbus City School District, Franklin County, Ohio, General Obligation Bonds, Series 2004,  12/14 at 100.00  AAA  2,345,780 
   5.250%, 12/01/25 (Pre-refunded 12/01/14) – FSA Insured       
2,385  Columbus, Ohio, Tax Increment Financing Bonds, Easton Project, Series 2004A, 5.000%,  6/14 at 100.00  BBB+  2,392,346 
   12/01/22 – AMBAC Insured       
2,205  Hamilton City School District, Ohio, General Obligation Bonds, Series 2005, 5.000%, 12/01/24 –  6/15 at 100.00  Baa1  2,240,523 
   MBIA Insured       
19,595  Hamilton County, Ohio, Sales Tax Bonds, Subordinate Lien, Series 2006, 4.250%, 12/01/32 –  12/16 at 100.00  A2  15,986,973 
   AMBAC Insured       
20,100  Lucas County, Ohio, Hospital Revenue Bonds, ProMedica Healthcare Obligated Group, Series 1999,  11/09 at 101.00  N/R  18,390,093 
   5.375%, 11/15/39 – AMBAC Insured       
3,000  Ross Local School District, Butler County, Ohio, General Obligation Bonds, Series 2003,  12/13 at 100.00  Aa3 (4)  3,453,990 
   5.000%, 12/01/28 (Pre-refunded 12/01/13) – FSA Insured       
51,935  Total Ohio      47,467,337 
  Oklahoma – 3.1% (1.9% of Total Investments)       
3,500  Oklahoma Capitol Improvement Authority, State Facilities Revenue Bonds, Series 2005F, 5.000%,  7/15 at 100.00  AA  3,647,070 
   7/01/24 – AMBAC Insured       
2,270  Oklahoma Housing Finance Agency, GNMA Collateralized Single Family Mortgage Revenue Bonds,  No Opt. Call  AAA  2,464,562 
   Series 1987A, 7.997%, 8/01/18 (Alternative Minimum Tax)       
21,000  Oklahoma Municipal Power Authority, Power Supply System Revenue Bonds, Series 2007, 4.500%,  1/17 at 100.00  17,487,120 
   1/01/47 – FGIC Insured       
5,245  Oklahoma State Industries Authority, Revenue Bonds, Oklahoma Medical Research Foundation,  2/11 at 100.00  A1  5,264,774 
   Series 2001, 5.250%, 2/01/21 – AMBAC Insured       
4,880  University of Oklahoma, Student Housing Revenue Bonds, Series 2004, 5.000%, 7/01/22 –  7/14 at 100.00  A1  4,888,198 
   AMBAC Insured       
36,895  Total Oklahoma      33,751,724 
  Oregon – 0.3% (0.2% of Total Investments)       
2,535  Oregon Department of Administrative Services, Certificates of Participation, Series 2005A,  5/15 at 100.00  AAA  2,633,155 
   5.000%, 5/01/25 – FSA Insured       
780  Oregon Housing and Community Services Department, Single Family Mortgage Revenue Bonds, Series  1/10 at 100.00  Aa2  780,624 
   1995A, 6.450%, 7/01/26 (Alternative Minimum Tax)       
3,315  Total Oregon      3,413,779 
  Pennsylvania – 3.4% (2.1% of Total Investments)       
7,925  Commonwealth Financing Authority, Pennsylvania, State Appropriation Lease Bonds, Series 2006A,  6/16 at 100.00  AAA  8,197,779 
   5.000%, 6/01/26 – FSA Insured (UB)       
1,800  Pennsylvania Higher Educational Facilities Authority, Revenue Bonds, Drexel University, Series  5/15 at 100.00  A+  1,803,420 
   2005A, 5.000%, 5/01/28 – MBIA Insured       
11,740  Pennsylvania Public School Building Authority, Lease Revenue Bonds, School District of  12/16 at 100.00  AAA  10,575,744 
   Philadelphia, Series 2006B, 4.500%, 6/01/32 – FSA Insured (UB)       
2,625  Pennsylvania Turnpike Commission, Turnpike Revenue Bonds, Series 2006A, 5.000%, 12/01/26 –  6/16 at 100.00  Aa3  2,688,893 
   AMBAC Insured       
6,335  Radnor Township School District, Delaware County, Pennsylvania, General Obligation Bonds,  8/15 at 100.00  Aa3  6,531,132 
   Series 2005B, 5.000%, 2/15/30 – FSA Insured       
  Reading School District, Berts County, Pennsylvania, General Obligation Bonds, Series 2005:       
3,285   5.000%, 1/15/22 – FSA Insured (UB)  1/16 at 100.00  AAA  3,479,406 
3,450   5.000%, 1/15/23 – FSA Insured (UB)  1/16 at 100.00  AAA  3,634,299 
37,160  Total Pennsylvania      36,910,673 
  Puerto Rico – 1.0% (0.6% of Total Investments)       
2,500  Puerto Rico Electric Power Authority, Power Revenue Bonds, Series 2005RR, 5.000%, 7/01/30  7/15 at 100.00  AAA  2,937,075 
   (Pre-refunded 7/01/15) – SYNCORA GTY Insured       
2,000  Puerto Rico Highway and Transportation Authority, Highway Revenue Bonds, Series 2003G, 5.250%,  7/13 at 100.00  BBB  1,917,820 
   7/01/19 – FGIC Insured       
1,550  Puerto Rico Municipal Finance Agency, Series 2005C, 5.250%, 8/01/21 – CIFG Insured  No Opt. Call  BBB–  1,507,282 
36,000  Puerto Rico Sales Tax Financing Corporation, Sales Tax Revenue Bonds, Series 2007A, 0.000%,  No Opt. Call  AA–  4,327,560 
   8/01/42 – FGIC Insured       
42,050  Total Puerto Rico      10,689,737 
  Rhode Island – 2.3% (1.5% of Total Investments)       
2,195  Providence Housing Development Corporation, Rhode Island, FHA-Insured Section 8 Assisted  1/10 at 100.00  AA–  2,197,897 
   Mortgage Revenue Refunding Bonds, Barbara Jordan Apartments, Series 1994A, 6.750%,       
   7/01/25 – MBIA Insured       
20,475  Rhode Island Depositors Economic Protection Corporation, Special Obligation Refunding Bonds,  2/11 at 100.00  A (4)  21,860,134 
   Series 1993B, 5.250%, 8/01/21 (Pre-refunded 2/01/11) – MBIA Insured       
1,405  Rhode Island Health & Educational Building Corporation, Higher Education Auxiliary Enterprise  9/14 at 100.00  A2  1,453,627 
   Revenue Bonds, Series 2004A, 5.500%, 9/15/24 – AMBAC Insured       
24,075  Total Rhode Island      25,511,658 
  South Carolina – 6.6% (4.1% of Total Investments)       
14,650  Anderson County School District 5, South Carolina, General Obligation Bonds, Series 2008,  2/18 at 100.00  AAA  15,172,566 
   Trust 1181, 9.469%, 2/01/38 – FSA Insured (IF)       
10,000  Beaufort County, South Carolina, Tax Increment Bonds, New River Redevelopment Project, Series  12/12 at 100.00  9,964,300 
   2002, 5.000%, 6/01/27 – MBIA Insured       
  Medical University Hospital Authority, South Carolina, FHA-Insured Mortgage Revenue Bonds,       
  Series 2004A:       
2,000   5.250%, 8/15/22 – MBIA Insured  8/14 at 100.00  2,049,620 
2,105   5.250%, 8/15/23 – MBIA Insured  8/14 at 100.00  2,150,784 
3,685  Piedmont Municipal Power Agency, South Carolina, Electric Revenue Bonds, Series 1988A, 0.000%,  No Opt. Call  Aaa  2,980,760 
   1/01/13 – AMBAC Insured (ETM)       
7,955  Piedmont Municipal Power Agency, South Carolina, Electric Revenue Bonds, Series 1988A, 0.000%,  No Opt. Call  N/R  6,818,151 
   1/01/13 – AMBAC Insured       
8,000  South Carolina JOBS Economic Development Authority, Industrial Revenue Bonds, South Carolina  11/12 at 100.00  A–  8,070,640 
   Electric and Gas Company, Series 2002A, 5.200%, 11/01/27 – AMBAC Insured       
10,000  South Carolina JOBS Economic Development Authority, Industrial Revenue Bonds, South Carolina  11/12 at 100.00  A–  8,979,900 
   Electric and Gas Company, Series 2002B, 5.450%, 11/01/32 – AMBAC Insured (Alternative       
   Minimum Tax)       
17,500  South Carolina Transportation Infrastructure Bank, Revenue Bonds, Series 2007A, 4.500%,  10/16 at 100.00  A1  15,781,325 
   10/01/34 – SYNCORA GTY Insured       
75,895  Total South Carolina      71,968,046 
  Tennessee – 0.6% (0.4% of Total Investments)       
6,455  Memphis-Shelby County Airport Authority, Tennessee, Airport Revenue Bonds, Series 2001A,  3/11 at 100.00  AAA  6,507,350 
   5.500%, 3/01/18 – FSA Insured (Alternative Minimum Tax)       
  Texas – 12.6% (7.9% of Total Investments)       
22,650  Brazos River Authority, Texas, Revenue Refunding Bonds, Houston Industries Inc., Series 1998C,  11/09 at 101.00  BBB+  21,854,759 
   5.125%, 5/01/19 – AMBAC Insured       
521  Capital Area Housing Finance Corporation, Texas, FNMA Backed Single Family Mortgage Revenue  4/12 at 106.00  Aaa  539,061 
   Refunding Bonds, Series 2002A-2, 6.300%, 4/01/35 – AMBAC Insured (Alternative Minimum Tax)       
12,500  Dallas-Ft. Worth International Airport, Texas, Joint Revenue Bonds, Series 2000A, 6.125%,  11/09 at 100.00  A+  12,503,250 
   11/01/35 – FGIC Insured (Alternative Minimum Tax)       
25,000  Harris County-Houston Sports Authority, Texas, Junior Lien Revenue Refunding Bonds, Series  11/11 at 100.00  19,619,000 
   2001B, 5.250%, 11/15/40 – MBIA Insured       
4,671  Houston Housing Finance Corporation, Texas, GNMA Collateralized Mortgage Multifamily Housing  9/11 at 105.00  Aaa  4,737,328 
   Revenue Bonds, RRG Apartments Project, Series 2001, 6.350%, 3/20/42       
  Houston, Texas, First Lien Combined Utility System Revenue Bonds, Series 2004A:       
4,000   5.250%, 5/15/24 – FGIC Insured  5/14 at 100.00  AA  4,146,840 
5,000   5.250%, 5/15/25 – MBIA Insured  5/14 at 100.00  AA  5,157,400 
17,500  Houston, Texas, Hotel Occupancy Tax and Special Revenue Bonds, Convention and Entertainment  9/11 at 100.00  A–  16,964,500 
   Project, Series 2001B, 5.250%, 9/01/33 – AMBAC Insured       
23,865  Jefferson County Health Facilities Development Corporation, Texas, FHA-Insured Mortgage  8/11 at 100.00  N/R  21,834,327 
   Revenue Bonds, Baptist Hospital of Southeast Texas, Series 2001, 5.500%, 8/15/41 –       
   AMBAC Insured       
140  Lower Colorado River Authority, Texas, Revenue Refunding and Improvement Bonds, Series 2001A,  5/11 at 100.00  A1 (4)  150,577 
   5.000%, 5/15/21 (Pre-refunded 5/15/11) – MBIA Insured       
8,065  Lower Colorado River Authority, Texas, Revenue Refunding and Improvement Bonds, Series 2001A,  5/11 at 100.00  A1  8,141,859 
   5.000%, 5/15/21 – MBIA Insured       
  Port of Houston Authority, Harris County, Texas, General Obligation Port Improvement Bonds,       
  Series 2001B:       
3,205   5.500%, 10/01/18 – FGIC Insured (Alternative Minimum Tax)  10/11 at 100.00  AAA  3,270,254 
3,375   5.500%, 10/01/19 – FGIC Insured (Alternative Minimum Tax)  10/11 at 100.00  AAA  3,430,451 
7,205  San Antonio, Texas, Airport System Improvement Revenue Bonds, Series 2001, 5.375%, 7/01/15 –  7/11 at 101.00  A+  7,353,495 
   FGIC Insured (Alternative Minimum Tax)       
7,550  Waco Health Facilities Development Corporation, Texas, Hillcrest Health System Project, FHA  8/16 at 100.00  6,830,712 
   Insured Mortgage Revenue Bonds, Series 2006A, 5.000%, 8/01/31 – MBIA Insured       
1,840  Ysleta Independent School District Public Facility Corporation, Texas, Lease Revenue Refunding  11/09 at 100.00  A+  1,843,110 
   Bonds, Series 2001, 5.375%, 11/15/24 – AMBAC Insured       
147,087  Total Texas      138,376,923 
  Utah – 1.6% (1.0% of Total Investments)       
2,000  Clearfield City, Utah, Sales Tax Revenue Bonds, Series 2003, 5.000%, 7/01/28 (Pre-refunded  7/13 at 100.00  AA– (4)  2,277,140 
   7/01/13) – FGIC Insured       
15,000  Utah Transit Authority, Sales Tax Revenue Bonds, Series 2008A, 5.000%, 6/15/32 – FSA Insured (UB)  6/18 at 100.00  AAA  15,366,300 
17,000  Total Utah      17,643,440 
  Virginia – 1.5% (0.9% of Total Investments)       
1,035  Loudoun County Industrial Development Authority, Virginia, Lease Revenue Bonds, Public Safety  6/14 at 100.00  AAA  1,132,911 
   Facilities, Series 2003A, 5.250%, 12/15/20 – FSA Insured       
4,840  Metropolitan Washington D.C. Airports Authority, Airport System Revenue Bonds, Series 2001A,  10/11 at 101.00  AA–  4,958,096 
   5.500%, 10/01/19 – MBIA Insured (Alternative Minimum Tax)       
10,000  Virginia Housing Development Authority, Commonwealth Mortgage Bonds, Series 2001H-1, 5.375%,  7/11 at 100.00  AAA  10,045,500 
   7/01/36 – NPFG Insured (UB)       
15,875  Total Virginia      16,136,507 
  Washington – 4.0% (2.5% of Total Investments)       
2,500  Grant County Public Utility District 2, Washington, Revenue Bonds, Wanapum Hydroelectric  1/15 at 100.00  Aa2  2,510,475 
   Development, Series 2005A, 5.000%, 1/01/29 – FGIC Insured       
3,500  King County School District 401, Highline, Washington, General Obligation Bonds, Series 2004,  12/14 at 100.00  AA+  3,675,840 
   5.000%, 10/01/24 – FGIC Insured       
5,000  King County, Washington, General Obligation Sewer Bonds, Series 2009, Trust 1W, 13.356%,  1/19 at 100.00  AAA  5,346,250 
   1/01/39 – AGC Insured (IF)       
4,345  King County, Washington, Sewer Revenue Bonds, Tender Option Bond Trust 3090, 12.938%,  7/17 at 100.00  AAA  4,307,459 
   1/01/39 – FSA Insured (IF)       
3,195  Kitsap County, Washington, Limited Tax General Obligation Bonds, Series 2000, 5.500%, 7/01/25  7/10 at 100.00  AA– (4)  3,344,079 
   (Pre-refunded 7/01/10) – AMBAC Insured       
4,250  Snohomish County Public Utility District 1, Washington, Generation System Revenue Bonds,  No Opt. Call  Aaa  5,388,448 
   Series 1989, 6.650%, 1/01/16 – FGIC Insured (ETM)       
  Tacoma, Washington, Solid Waste Utility Revenue Refunding Bonds, Series 2006:       
3,890   5.000%, 12/01/24 – SYNCORA GTY Insured  12/16 at 100.00  AA  4,015,025 
4,085   5.000%, 12/01/25 – SYNCORA GTY Insured  12/16 at 100.00  AA  4,188,024 
4,290   5.000%, 12/01/26 – SYNCORA GTY Insured  12/16 at 100.00  AA  4,374,127 
5,945  Washington State, General Obligation Bonds, Series 2009, Trust 1212, 12.408%, 7/01/31 – FSA  7/16 at 100.00  AAA  6,362,993 
   Insured (IF)       
41,000  Total Washington      43,512,720 
  Wisconsin – 2.6% (1.6% of Total Investments)       
15,000  Wisconsin Health and Educational Facilities Authority, Revenue Bonds, Marshfield Clinic,  8/09 at 100.00  AA–  13,657,200 
   Series 1997, 5.750%, 2/15/27 – MBIA Insured       
290  Wisconsin, General Obligation Bonds, Series 2004-3, 5.250%, 5/01/20 – FGIC Insured  5/14 at 100.00  Aa3  312,055 
2,600  Wisconsin, General Obligation Bonds, Series 2004-3, 5.250%, 5/01/20 (Pre-refunded 5/01/14) –  5/14 at 100.00  Aa3 (4)  3,022,240 
   FGIC Insured       
10,945  Wisconsin, General Obligation Bonds, Series 2004-4, 5.000%, 5/01/20 – MBIA Insured  5/14 at 100.00  AA  11,663,539 
28,835  Total Wisconsin      28,655,034 
$      1,943,050  Total Investments (cost $1,770,555,227) – 158.9%      1,741,777,564 
  Floating Rate Obligations – (10.8)%      (118,133,333)
  Other Assets Less Liabilities – 4.2%      45,528,739 
  Auction Rate Preferred Shares, at Liquidation Value – (52.3)% (5)      (573,300,000)
  Net Assets Applicable to Common Shares – 100%      $ 1,095,872,970 

Fair Value Measurements

During the current fiscal period, the Fund adopted the provisions of Statement of Financial Accounting Standards No. 157 (SFAS No. 157) “Fair Value Measurements.” SFAS No. 157 defines fair value, establishes a framework for measuring fair value in generally accepted accounting principles and expands disclosure about fair value measurements. In determining the value of the Fund’s investments various inputs are used. These inputs are summarized in the three broad levels listed below:

Level 1 – Quoted prices in active markets for identical securities.

Level 2 – Other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.).

Level 3 – Significant unobservable inputs (including management’s assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities. The following is a summary of the Fund’s fair value measurements as of July 31, 2009:

  Level 1  Level 2  Level 3  Total 
Investments:         
  Municipal Bonds  $ —  $1,741,777,564  $ —  $1,741,777,564 

Income Tax Information

The following information is presented on an income tax basis. Differences between amounts for financial statement and federal income tax purposes are primarily due to timing differences in recognizing taxable market discount, timing differences in recognizing certain gains and losses on investment transactions and the treatment of investments in inverse floating rate transactions subject to Statement of Financial Accounting Standards No. 140 (SFAS No. 140), if any. To the extent that differences arise that are permanent in nature, such amounts are reclassified within the capital accounts on the Statement of Assets and Liabilities presented in the annual report, based on their federal tax basis treatment; temporary differences do not require reclassification. Temporary and permanent differences do not impact the net asset value of the Fund.

At July 31, 2009, the cost of investments was $1,651,402,742.

Gross unrealized appreciation and gross unrealized depreciation of investments at July 31, 2009, were as follows:

Gross unrealized:   
  Appreciation  $  66,326,955 
  Depreciation  (94,079,104) 
Net unrealized appreciation (depreciation) of investments  $(27,752,149) 

  Primarily all of the Fund’s net assets (including net assets attributable to Auction Rate Preferred shares) 
  are invested in municipal securities that guarantee the timely payment of principal and interest. 
(1)  All percentages shown in the Portfolio of Investments are based on net assets applicable to Common 
  shares unless otherwise noted. 
(2)  Optional Call Provisions: Dates (month and year) and prices of the earliest optional call or redemption. 
  There may be other call provisions at varying prices at later dates. Certain mortgage-backed securities 
  may be subject to periodic principal paydowns. 
(3)  Ratings: Using the higher of Standard & Poor’s Group (“Standard & Poor’s”) or Moody’s Investor Service, 
  Inc. (“Moody’s”) rating. Ratings below BBB by Standard & Poor's or Baa by Moody’s are considered to be 
  below investment grade. 
  The Portfolio of Investments may reflect the ratings on certain bonds whose insurer has experienced 
  downgrades as of the end of the reporting period. Subsequent to the reporting period, and during the 
  period this Portfolio of Investments was prepared, there may have been reductions to the ratings of 
  certain bonds resulting from changes to the ratings of the underlying insurers both during the period and 
  after period end. Such reductions would likely reduce the effective rating of many of the bonds insured by 
  that insurer or insurers presented at period end. 
(4)  Backed by an escrow or trust containing sufficient U.S. Government or U.S. Government agency securities 
  which ensure the timely payment of principal and interest. Such investments are normally considered to 
  be equivalent to AAA rated securities. 
(5)  Auction Rate Preferred Shares, at Liquidation Value as a percentage of Total Investments is 32.9%. 
N/R  Not rated. 
(ETM)  Escrowed to maturity. 
(IF)  Inverse floating rate investment. 
(UB)  Underlying bond of an inverse floating rate trust reflected as a financing transaction pursuant to the 
  provisions of SFAS No. 140. 


Item 2. Controls and Procedures.

  1. The registrant's principal executive and principal financial officers, or persons performing similar functions, have concluded that the registrant's disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940, as amended (the "1940 Act") (17 CFR 270.30a-3(c))) are effective, as of a date within 90 days of the filing date of this report that includes the disclosure required by this paragraph, based on their evaluation of the controls and procedures required by Rule 30a-3(b) under the 1940 Act (17 CFR 270.30a-3(b)) and Rule 13a-15(b) or 15d-15(b) under the Securities Exchange Act of 1934 (17 CFR 240.13a-15(b) or 240.15d-15(b)).
  2. There were no changes in the registrant's internal control over financial reporting (as defined in Rule 30a-3(d) under the 1940 Act (17 CFR 270.30a-3(d)) that occurred during the registrant's last fiscal quarter that have materially affected, or are reasonably likely to materially affect, the registrant's internal control over financial reporting.

Item 3. Exhibits.

File as exhibits as part of this Form a separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the 1940 Act (17 CFR 270.30a-2(a)), exactly as set forth below: See EX-99 CERT attached hereto.


SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

(Registrant)         Nuveen Insured Municipal Opportunity Fund, Inc.         

By (Signature and Title)          /s/ Kevin J. McCarthy                    
                                                  Kevin J. McCarthy
                                                  Vice President and Secretary

Date         September 29, 2009        

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By (Signature and Title)         /s/ Gifford R. Zimmerman                    
                                                 Gifford R. Zimmerman
                                                 Chief Administrative Officer (principal executive officer) 

Date         September 29, 2009        

By (Signature and Title)         /s/ Stephen D. Foy                              
                                                 Stephen D. Foy
                                                 Vice President and Controller (principal financial officer) 

Date        September 29, 2009