nq2.htm



 
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 811-22425
 
Nuveen Build America Bond Opportunity Fund
(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:            3/31          
 
Date of reporting period:         12/31/12         
 
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 Build America Bond Opportunity Fund (NBD) 
     
   
December 31, 2012 
     
 
 
Principal 
   
Optional Call 
   
Amount (000) 
 
Description (1) 
Provisions (2) 
Ratings (3) 
Value 
   
California – 20.5% (18.5% of Total Investments) 
     
$ 1,030 
 
Bay Area Toll Authority, California, Revenue Bonds, San Francisco Bay Area Toll Bridge, 
No Opt. Call 
A+ 
$ 1,490,853 
   
Subordinate Lien, Build America Federally Taxable Bond Series 2010S-1, 7.043%, 4/01/50 
     
1,500 
 
California State Public Works Board, Lease Revenue Bonds, Various Capital Projects, Build 
No Opt. Call 
A2 
1,928,385 
   
America Taxable Bond Series 2009G-2, 8.361%, 10/01/34 
     
2,000 
 
Los Angeles Community College District, Los Angeles County, California, General Obligation 
No Opt. Call 
Aa1 
5,803,900 
   
Bonds, Tender Option Bond Trust TN027, 29.762%, 8/01/49 (IF) (4) 
     
3,000 
 
Los Angeles County Public Works Financing Authority, California, Lease Revenue Bonds, Mulitple 
No Opt. Call 
AA– 
3,978,330 
   
Capital Projects I, Build America Taxable Bond Series 2010B, 7.618%, 8/01/40 
     
2,650 
 
Los Angeles Department of Airports, California, Revenue Bonds, Los Angeles International 
No Opt. Call 
AA– 
3,449,929 
   
Airport, Build America Taxable Bonds, Series 2009C, 6.582%, 5/15/39 
     
2,000 
 
Los Angeles Department of Water and Power, California, Water System Revenue Bonds, Tender 
No Opt. Call 
AA 
6,644,100 
   
Option Bond Trust T0003, 29.807%, 7/01/42 (IF) (4) 
     
1,000 
 
Oakland Redevelopment Agency, California, Subordinated Housing Set Aside Revenue Bonds, 
No Opt. Call 
A
1,132,890 
   
Federally Taxable Series 2011A-T, 7.500%, 9/01/19 
     
2,175 
 
San Diego County Regional Transportation Commission, California, Sales Tax Revenue Bonds, 
No Opt. Call 
AAA 
2,887,291 
   
Build America Taxable Bonds Series 2010A, 5.911%, 4/01/48 
     
2,000 
 
San Francisco City and County, California, Certificates of Participation, 525 Golden Gate 
No Opt. Call 
AA– 
3,045,800 
   
Avenue, San Francisco Public Utilities Commission Office Project, Tender Option Bond Trust 
     
   
B001, 29.403%, 11/01/41 (IF) 
     
315 
 
Stanton Redevelopment Agency, California, Consolidated Project Tax Allocation Bonds, Series 
No Opt. Call 
A– 
343,372 
   
2011A, 7.000%, 12/01/19 
     
3,000 
 
The Regents of the University of California, Medical Center Pooled Revenue Bonds, Build 
No Opt. Call 
Aa2 
3,929,670 
   
America Taxable Bonds, Series 2010H, 6.548%, 5/15/48 
     
20,670 
 
Total California 
   
34,634,520 
   
Colorado – 4.7% (4.2% of Total Investments) 
     
4,000 
 
Colorado State Bridge Enterprise Revenue Bonds, Federally Taxable Build America Series 2010A, 
No Opt. Call 
AA 
5,177,480 
   
6.078%, 12/01/40 
     
2,000 
 
Regional Transportation District, Colorado, Sales Tax Revenue Bonds, Fastracks Project, Build 
No Opt. Call 
AA+ 
2,730,600 
   
America Series 2010B, 5.844%, 11/01/50 
     
6,000 
 
Total Colorado 
   
7,908,080 
   
Connecticut – 0.7% (0.6% of Total Investments) 
     
1,000 
 
Harbor Point Infrastructure Improvement District, Connecticut, Special Obligation Revenue 
4/20 at 100.00 
N/R 
1,166,010 
   
Bonds, Harbor Point Project, Federally Taxable – Issuer Subsidy – Recovery Zone Economic 
     
   
Development Bond Series 2010B, 12.500%, 4/01/39 
     
   
District of Columbia – 0.6% (0.5% of Total Investments) 
     
800 
 
District of Columbia, Income Tax Secured Revenue Bonds, Build America Taxable Bonds, Series 
No Opt. Call 
AAA 
997,656 
   
2009E, 5.591%, 12/01/34 (4) 
     
   
Georgia – 3.4% (3.1% of Total Investments) 
     
2,000 
 
Georgia Municipal Electric Authority, Plant Vogtle Units 3 & 4 Project J Bonds, Taxable Build 
No Opt. Call 
A+ 
2,382,280 
   
America Bonds Series 2010A, 6.637%, 4/01/57 
     
3,000 
 
Georgia Municipal Electric Authority, Plant Vogtle Units 3 & 4 Project P Bonds, Refunding 
No Opt. Call 
A– 
3,367,560 
   
Taxable Build America Bonds Series 2010A, 7.055%, 4/01/57 
     
5,000 
 
Total Georgia 
   
5,749,840 
   
Illinois – 15.3% (13.8% of Total Investments) 
     
3,575 
 
Chicago Transit Authority, Illinois, Sales Tax Receipts Revenue Bonds, Federally Taxable Build 
No Opt. Call 
AA 
4,017,764 
   
America Bonds, Series 2010B, 6.200%, 12/01/40 
     
1,010 
 
Chicago, Illinois, General Airport Revenue Bonds, O’Hare International Airport, Third Lien, 
1/20 at 100.00 
A2 
1,177,236 
   
Build America Taxable Bond Series 2010B, 6.845%, 1/01/38 
     
           
5,160 
 
Chicago, Illinois, Wastewater Transmission Revenue Bonds, Build America Taxable Bond Series 
No Opt. Call 
AA 
6,577,607 
   
2010B, 6.900%, 1/01/40 (4) 
     
3,545 
 
Chicago, Illinois, Water Revenue Bonds, Taxable Second Lien Series 2010B, 6.742%, 11/01/40 
No Opt. Call 
AA 
4,834,210 
1,000 
 
Cook County, Illinois, General Obligation Bonds, Build America Taxable Bonds, Series 2010D, 
No Opt. Call 
AA 
1,156,420 
   
6.229%, 11/15/34 
     
500 
 
Illinois Finance Authority, Revenue Bonds, Illinois Institute of Technology, Refunding Series 
3/13 at 100.00 
Baa3 
493,000 
   
2006A, 6.100%, 4/01/15 
     
2,000 
 
Illinois State, General Obligation Bonds, Build America Taxable Bonds, Series 2010-5, 
No Opt. Call 
A
2,435,240 
   
7.350%, 7/01/35 
     
4,110 
 
Illinois Toll Highway Authority, Toll Highway Revenue Bonds, Build America Taxable Bonds, 
No Opt. Call 
AA– 
5,114,813 
   
Senior Lien Series 2009A, 6.184%, 1/01/34 
     
20,900 
 
Total Illinois 
   
25,806,290 
   
Indiana – 2.7% (2.4% of Total Investments) 
     
3,480 
 
Indianapolis Local Public Improvement Bond Bank, Indiana, Build America Taxable Bonds, Series 
No Opt. Call 
AA+ 
4,602,022 
   
2010B-2, 6.116%, 1/15/40 
     
   
Kentucky – 2.3% (2.1% of Total Investments) 
     
3,000 
 
Louisville and Jefferson County Metropolitan Sewer District, Kentucky, Sewer and Drainage 
No Opt. Call 
AA 
3,926,670 
   
System Revenue Bonds, Build America Taxable Bonds Series 2010A, 6.250%, 5/15/43 
     
   
Massachusetts – 3.1% (2.8% of Total Investments) 
     
2,000 
 
Massachusetts, Transportation Fund Revenue Bonds, Accelerated Bridge Program, Tender Option 
No Opt. Call 
AAA 
5,167,900 
   
Bond Trust T0004, 25.756%, 6/01/40 (IF) (4) 
     
   
Michigan – 4.3% (3.9% of Total Investments) 
     
3,000 
 
Detroit City School District, Wayne County, Michigan, General Obligation Bonds, Build America 
5/20 at 100.00 
Aa2 
3,225,540 
   
Taxable Bond Series 2010B, 6.845%, 5/01/40 
     
2,060 
 
Michigan Tobacco Settlement Finance Authority, Tobacco Settlement Asset-Backed Revenue Bonds, 
6/22 at 100.00 
B2 
1,702,981 
   
Taxable Turbo Series 2006A, 7.309%, 6/01/34 
     
2,000 
 
Wayne County Building Authority, Michigan, General Obligation Bonds, Jail Facilities, 
12/20 at 100.00 
BBB+ 
2,365,080 
   
Federally Taxable Recovery Zone Economic Development Series 2010, 10.000%, 12/01/40 
     
7,060 
 
Total Michigan 
   
7,293,601 
   
Mississippi – 1.8% (1.6% of Total Investments) 
     
2,585 
 
Mississippi State, General Obligation Bonds, Build America Taxable Bond Series 2010F, 
No Opt. Call 
AA+ 
3,100,423 
   
5.245%, 11/01/34 
     
   
Missouri – 1.1% (1.0% of Total Investments) 
     
250 
 
Curators of the University of Missouri, System Facilities Revenue Bonds, Build America Taxable 
No Opt. Call 
AA+ 
329,065 
   
Bonds, Series 2009A, 5.960%, 11/01/39 
     
1,150 
 
Curators of the University of Missouri, System Facilities Revenue Bonds, Build America Taxable 
No Opt. Call 
AA+ 
1,486,559 
   
Bonds, Series 2010, 5.792%, 11/01/41 
     
1,400 
 
Total Missouri 
   
1,815,624 
   
Nevada – 2.6% (2.3% of Total Investments) 
     
1,950 
 
Clark County, Nevada, Airport Revenue Bonds, Senior Lien Series 2009B, 6.881%, 7/01/42 
7/19 at 100.00 
Aa2 
2,256,696 
1,500 
 
Clark County, Nevada, Airport System Revenue, Taxable Direct Payment Build America Bonds, 
No Opt. Call 
Aa2 
2,137,995 
   
Senior Series 2010C, 6.820%, 7/01/45 
     
3,450 
 
Total Nevada 
   
4,394,691 
   
New Jersey – 7.1% (6.4% of Total Investments) 
     
3,055 
 
New Jersey Transportation Trust Fund Authority, Transportation System Bonds, Build America 
No Opt. Call 
A+ 
3,681,642 
   
Bonds Issuer Subsidy Program, Series 2010C, 5.754%, 12/15/28 
     
4,000 
 
New Jersey Turnpike Authority, Revenue Bonds, Build America Taxable Bonds, Series 2010A, 
No Opt. Call 
A+ 
5,696,960 
   
7.102%, 1/01/41 
     
2,070 
 
Rutgers State University, New Jersey, Revenue Bonds, Build America Taxable Bond Series 2010H, 
No Opt. Call 
AA 
2,601,431 
   
5.665%, 5/01/40 
     
9,125 
 
Total New Jersey 
   
11,980,033 
   
New York – 14.2% (12.8% of Total Investments) 
     
2,000 
 
Dormitory Authority of the State of New York, State Personal Income Tax Revenue Bonds, Tender 
No Opt. Call 
AAA 
4,426,100 
   
Option Bond Trust B004, 25.109%, 3/15/40 (IF) 
     
2,025 
 
Metropolitan Transportation Authority, New York, Transportation Revenue Bonds, Federally 
No Opt. Call 
A
2,648,518 
   
Taxable Issuer Subsidy Build America Bonds, Series 2010A, 6.668%, 11/15/39 
     
3,000 
 
New York City Municipal Water Finance Authority, New York, Water and Sewer System Revenue 
No Opt. Call 
AA+ 
3,744,330 
   
Bonds, Second Generation Resolution, Build America Taxable Bonds, Fiscal 2011 Series AA, 
     
   
5.440%, 6/15/43 (4) 
     
2,000 
 
New York City Municipal Water Finance Authority, New York, Water and Sewer System Revenue 
No Opt. Call 
AA+ 
5,506,500 
   
Bonds, Second Generation Resolution, Taxable Tender Option Bonds Trust T30001-2, 
     
   
26.799%, 6/15/44 (IF) 
     
3,500 
 
New York City Transitional Finance Authority, New York, Building Aid Revenue Bonds, Build 
No Opt. Call 
AA– 
4,655,630 
   
America Taxable Bond Fiscal 2011 Series 2010S-1B, 6.828%, 7/15/40 
     
2,500 
 
New York City, New York, General Obligation Bonds, Federally Taxable Build America Bonds, 
12/20 at 100.00 
AA 
3,080,500 
   
Series 2010-F1, 6.646%, 12/01/31 
     
15,025 
 
Total New York 
   
24,061,578 
   
North Carolina – 1.0% (0.9% of Total Investments) 
     
1,400 
 
North Carolina Turnpike Authority, Triangle Expressway System State Annual Appropriation 
1/19 at 100.00 
AA 
1,612,758 
   
Revenue Bonds, Federally Taxable Issuer Subsidy Build America Bonds, Series 2009B, 
     
   
6.700%, 1/01/39 
     
   
Ohio – 3.9% (3.5% of Total Investments) 
     
3,000 
 
American Municipal Power Inc., Ohio, Meldahl Hydroelectric Projects Revenue Bonds, Federally 
No Opt. Call 
A
4,080,870 
   
Taxable Build America Bonds, Series 2010B, 7.499%, 2/15/50 
     
2,150 
 
Northeast Ohio Regional Sewer District, Wastewater Improvement Revenue Bonds, Build America 
11/20 at 100.00 
AA+ 
2,485,701 
   
Taxable Bonds, Series 2010, 6.038%, 11/15/40 
     
5,150 
 
Total Ohio 
   
6,566,571 
   
Pennsylvania – 1.8% (1.6% of Total Investments) 
     
2,500 
 
Pennsylvania Turnpike Commission, Turnpike Revenue Bonds, Build America Taxable Bonds, Series 
No Opt. Call 
Aa3 
2,980,475 
   
2010B, 5.511%, 12/01/45 
     
   
South Carolina – 9.1% (8.1% of Total Investments) 
     
2,000 
 
South Carolina Public Service Authority, Electric System Revenue Bonds, Santee Cooper, 
No Opt. Call 
AA– 
2,683,020 
   
Federally Taxable Build America Series 2010C, 6.454%, 1/01/50 
     
205 
 
South Carolina Public Service Authority, Electric System Revenue Bonds, Santee Cooper, 
No Opt. Call 
AA– 
555,048 
   
Federally Taxable Build America Tender Option Bond Trust T30002, 29.331%, 1/01/50 (IF) 
     
8,985 
 
South Carolina Public Service Authority, Electric System Revenue Bonds, Santee Cooper, 
No Opt. Call 
AA– 
12,053,467 
   
Federally Taxable Build America Series 2010C, 6.454%, 1/01/50 (UB) 
     
11,190 
 
Total South Carolina 
   
15,291,535 
   
Tennessee – 2.1% (1.9% of Total Investments) 
     
3,000 
 
Metropolitan Government Nashville & Davidson County Convention Center Authority, Tennesse, 
No Opt. Call 
Aa2 
3,624,840 
   
Tourism Tax Revenue Bonds, Build America Taxable Bonds, Subordinate Lien Series 2010B, 
     
   
6.731%, 7/01/43 
     
   
Texas – 5.3% (4.8% of Total Investments) 
     
1,810 
 
Board of Regents, University of Texas System, Financing System Revenue Bonds, Build America 
8/19 at 100.00 
AAA 
2,137,429 
   
Taxable Bonds, Series 2009B, 6.276%, 8/15/41 
     
2,000 
 
Dallas Area Rapid Transit, Texas, Senior Lien Sales Tax Revenue Bonds, Build America Taxable 
No Opt. Call 
AA+ 
2,703,620 
   
Bonds, Series 2009B, 5.999%, 12/01/44 
     
2,000 
 
Dallas Convention Center Hotel Development Corporation, Texas, Hotel Revenue Bonds, Build 
No Opt. Call 
A+ 
2,414,420 
   
America Taxable Bonds, Series 09B, 7.088%, 1/01/42 
     
1,500 
 
North Texas Tollway Authority, System Revenue Bonds, Subordinate Lien Taxable Revenue Bonds, 
2/20 at 100.00 
Baa3 
1,760,100 
   
Federally Taxable Build America Bonds, Series 2010-B2, 8.910%, 2/01/30 
     
7,310 
 
Total Texas 
   
9,015,569 
   
Virginia – 2.8% (2.5% of Total Investments) 
     
2,110 
 
Metropolitan Washington D.C. Airports Authority, Virginia, Dulles Toll Road Revenue Bonds, 
No Opt. Call 
BBB+ 
2,547,908 
   
Series 2009D, 7.462%, 10/01/46 – AGC Insured 
     
3,000 
 
Tobacco Settlement Financing Corporation of Virginia, Tobacco Settlement Asset Backed Bonds, 
No Opt. Call 
B2 
2,121,480 
   
Refunding Senior Lien Series 2007A1, 6.706%, 6/01/46 
     
5,110 
 
Total Virginia 
   
4,669,388 
   
Washington – 0.7% (0.7% of Total Investments) 
     
1,000 
 
Washington State Convention Center Public Facilities District, Lodging Tax Revenue Bonds, 
No Opt. Call 
Aa3 
1,226,160 
   
Build America Taxable Bond Series 2010B, 6.790%, 7/01/40 
     
$ 138,155 
 
Total Investments (cost $141,976,489) – 111.1% 
   
187,592,234 
   
Borrowings – (6.8)% (5), (6) 
   
(11,500,000) 
   
Floating Rate Obligations – (4.3)% 
   
(7,190,000) 
   
Other Assets Less Liabilities – 0.0% (7) 
   
(23,216) 
   
Net Assets Applicable to Common Shares – 100% 
   
$ 168,879,018 
 
 
 
 
 

 
 

 
                 
Investments in Derivatives as of December 31, 2012 
       
Swaps outstanding: 
               
   
Fund 
   
Fixed Rate 
   
Unrealized 
 
Notional 
Pay/Receive 
Floating Rate 
Fixed Rate 
Payment 
Effective
Termination 
Appreciation 
Counterparty 
Amount 
Floating Rate 
Index 
(Annualized) 
Frequency 
Date (8) 
Date
(Depreciation) (7) 
Barclays Bank PLC 
$11,200,000 
Receive 
1-Month USD-LIBOR 
2.240% 
Monthly 
12/17/10 
12/17/15 
$ (620,871) 
Barclays Bank PLC 
14,750,000 
Receive 
1-Month USD-LIBOR 
1.450 
Monthly 
10/01/14 
10/01/18 
(125,909) 
Barclays Bank PLC 
20,000,000 
Receive 
3-Month USD-LIBOR 
2.863 
Semi-Annually 
2/14/13 
2/14/42 
(310,528) 
Morgan Stanley 
11,200,000 
Receive 
1-Month USD-LIBOR 
1.295 
Monthly 
12/17/10 
12/17/13 
(119,905) 
Morgan Stanley 
14,750,000 
Receive 
1-Month USD-LIBOR 
1.875 
Monthly 
10/01/14 
6/01/20 
(195,139) 
Morgan Stanley 
15,000,000 
Receive 
3-Month USD-LIBOR 
3.035 
Semi-Annually 
2/21/14 
2/21/41 
(388,649) 
Morgan Stanley 
18,000,000 
Receive 
3-Month USD-LIBOR 
3.098 
Semi-Annually 
1/24/14 
1/24/41 
(728,888) 
               
$(2,489,889) 
 
 
Fair Value Measurements
 
Fair value is defined as the price that the Fund would receive upon selling an investment or transferring a liability in an orderly transaction to an independent buyer in the principal or most advantageous market for the investment. A three-tier hierarchy is used to maximize the use of observable market data and minimize the use of unobservable inputs and to establish classification of fair value measurements for disclosure purposes. Observable inputs reflect the assumptions market participants would use in pricing the asset or liability. Observable inputs are based on market data obtained from sources independent of the reporting entity. Unobservable inputs reflect the reporting entity’s own assumptions about the assumptions market participants would use in pricing the asset or liability. Unobservable inputs are based on the best information available in the circumstances. The following is a summary of the three-tiered hierarchy of valuation input levels.
 
Level 1 – Inputs are unadjusted and prices are determined using quoted prices in active markets for identical securities.
 
Level 2 – Prices are determined using other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.).
 
Level 3 – Prices are determined using significant unobservable inputs (including management's assumptions in determining the fair value of investments).
 
The inputs or methodologies used for valuing securities are not an indication of the risks associated with investing in those securities. The following is a summary of the Fund's fair value measurements as of the end of the reporting period:
         
 
Level 1 
Level 2 
Level 3 
Total 
Long-Term Investments: 
       
Municipal Bonds 
$ — 
$187,592,234 
$ — 
$187,592,234 
Derivatives: 
       
Swaps* 
(2,489,889) 
(2,489,889) 
Total 
$ — 
$185,102,345 
$ — 
$185,102,345 
* Represents net unrealized appreciation (depreciation) as reported in the Fund's Portfolio of Investments. 
     
 
 
The Nuveen funds’ Board of Directors/Trustees is responsible for the valuation process and has delegated the oversight of the daily valuation process to the Adviser’s Valuation Committee. The Valuation Committee, pursuant to the valuation policies and procedures adopted by the Board of Directors/Trustees, is responsible for making fair value determinations, evaluating the effectiveness of the funds’ pricing policies, and reporting to the Board of Directors/Trustees. The Valuation Committee is aided in its efforts by the Adviser’s dedicated Securities Valuation Team, which is responsible for administering the daily valuation process and applying fair value methodologies as approved by the Valuation Committee. When determining the reliability of independent pricing services for investments owned by the funds, the Valuation Committee, among other things, conducts due diligence reviews of the pricing services and monitors the quality of security prices received through various testing reports conducted by the Securities Valuation Team.
 
The Valuation Committee will consider pricing methodologies it deems relevant and appropriate when making fair value determinations. Examples of possible methodologies include, but are not limited to, multiple of earnings; discount from market of a similar freely traded security; discounted cash-flow analysis; book value or a multiple thereof; risk premium/yield analysis; yield to maturity; and/or fundamental investment analysis. The Valuation Committee will also consider factors it deems relevant and appropriate in light of the facts and circumstances. Examples of possible factors include, but are not limited to, the type of security; the issuer’s financial statements; the purchase price of the security; the discount from market value of unrestricted securities of the same class at the time of purchase; analysts’ research and observations from financial institutions; information regarding any transactions or offers with respect to the security; the existence of merger proposals or tender offers affecting the security; the price and extent of public trading in similar securities of the issuer or comparable companies; and the existence of a shelf registration for restricted securities.
 
For each portfolio security that has been fair valued pursuant to the policies adopted by the Board of Directors/Trustees, the fair value price is compared against the last available and next available market quotations. The Valuation Committee reviews the results of such testing and fair valuation occurrences are reported to the Board of Directors/Trustees.
 
Derivative Instruments and Hedging Activities
 
The Fund records derivative instruments at fair value, with changes in fair value recognized on the Statement of Operations, when applicable. Even though the Fund’s investments in derivatives may represent economic hedges, they are not considered to be hedge transactions for financial reporting purposes. The following table presents the fair value of all derivative instruments held by the Fund as of December 31, 2012, the location of these instruments on the Statement of Assets and Liabilities, and the primary underlying risk exposure.
 
 
 
             
    Location on the Statement of Assets and Liabilities 
Underlying 
Derivative 
Asset Derivatives   
Liability Derivatives 
Risk Exposure 
Instrument 
Location 
Value 
 
Location 
Value 
Interest Rate 
Swaps 
$ — 
 
Unrealized depreciation 
 
         
on swaps 
$(2,489,889) 
 
 
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 certain gains and losses on investment transactions and the treatment of investments in inverse floating rate securities reflected as financing transactions, 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.
 
As of December 31, 2012, the cost of investments (excluding investments in derivatives) was $134,847,367.
 
Gross unrealized appreciation and gross unrealized depreciation of investments (excluding investments in derivatives) as of December 31, 2012, were as follows:
   
Gross unrealized: 
 
Appreciation 
$45,632,634 
Depreciation 
(81,182) 
Net unrealized appreciation (depreciation) of investments 
$45,551,452 
 
 
     
 
(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 highest of Standard & Poor’s Group ("Standard & Poor's"), Moody’s Investors 
   
Service, Inc. ("Moody's") or Fitch, Inc. ("Fitch") rating. Ratings below BBB by Standard & Poor’s, Baa by 
   
Moody’s or BBB by Fitch are considered to be below investment grade. Holdings designated N/R are 
   
not rated by any of these national rating agencies. 
 
(4) 
Investment, or portion of investment, has been pledged to collateralize the net payment obligations 
   
for investments in derivatives and/or inverse floating rate transactions. 
 
(5) 
Borrowings as a percentage of Total Investments is 6.1%. 
 
(6) 
The Fund segregates 100% of its eligible investments in the Portfolio of Investments as collateral 
   
for Borrowings. 
 
(7) 
Other Assets Less Liabilities includes the Unrealized Appreciation (Depreciation) of derivative 
   
instruments as listed within Investments in Derivatives as of the end of the reporting period. 
 
(8) 
Effective date represents the date on which both the Fund and Counterparty commence interest 
   
payment accruals on each swap contract. 
 
N/R 
Not rated. 
 
(IF) 
Inverse floating rate investment. 
 
(UB) 
Underlying bond of an inverse floating rate trust reflected as a financing transaction. 
 
USD-LIBOR 
United States Dollar-London Inter-Bank Offered Rate. 
 
 

 
 
 

 
 
Item 2. Controls and Procedures.

a.  
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)).
 
 
b.  
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 Build America Bond Opportunity Fund 
 
By (Signature and Title)     /s/ Kevin J. McCarthy                    
                                                   Kevin J. McCarthy
                                                   Vice President and Secretary
 
Date:         March 1, 2013        
 
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:         March 1, 2013        
 
By (Signature and Title)     /s/ Stephen D. Foy                              
                                                   Stephen D. Foy
                                                  Vice President and Controller (principal financial officer) 
 
Date:         March 1, 2013