UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED
MANAGEMENT INVESTMENT COMPANIES

Form N-CSR is to be used by management investment companies to file reports with the Commission not later than 10 days after the transmission to stockholders of any report that is required to be transmitted to stockholders under Rule 30e-1 under the Investment Company Act of 1940 (17 CFR 270.30e-1). The Commission may use the information provided on Form N-CSR in its regulatory, disclosure review, inspection, and policymaking roles.

A registrant is required to disclose the information specified by Form N-CSR, and the Commission will make this information public. A registrant is not required to respond to the collection of information contained in Form N-CSR 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 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. ss. 3507.

ITEM 1. REPORTS TO STOCKHOLDERS.

Closed-End Funds

Nuveen Investments

Closed-End Funds

Seeks high current income from portfolios of senior corporate loans.

Annual Report

July 31, 2013

Nuveen Senior
Income Fund

NSL

Nuveen Floating
Rate Income Fund

JFR

Nuveen Floating
Rate Income
Opportunity Fund

JRO

Nuveen Short
Duration Credit
Opportunities Fund

JSD

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Table of Contents

Chairman's
Letter to Shareholders

Dear Shareholders,

I am pleased to have this opportunity to introduce myself to you as the new independent chairman of the Nuveen Fund Board, effective July 1, 2013. I am honored to have been selected as chairman, with its primary responsibility to serve the interests of the Nuveen fund shareholders. My predecessor, Robert Bremner, was the first independent director to serve as chairman of the Board and I, and my fellow Board members, plan to continue his legacy of strong independent oversight of your funds.

The global economy has hit major turning points over the last several months to a year. The developed world is gradually recovering from their financial crisis while the emerging markets appear to be struggling with the downshift of China's growth potential. Japan is entering a new era of growth after decades of economic stagnation and many of the Eurozone nations appear to be exiting their recession. Despite the positive events, there are still potential risks. Middle East tensions, rising oil prices, defaults in Europe and fallout from the financial stress in emerging markets could all reverse the recent progress in the global economy.

On the domestic front, the U.S. economy is experiencing sustainable slow growth. Corporate fundamentals are strong as earnings per share and corporate cash are at the highest level in two decades. Unemployment is trending down and the housing market has experienced a rebound, each assisting the positive economic scenario. However, there are some issues to be watched. Interest rates are expected to increase but significant uncertainty about the timing remains. Another potential fiscal cliff in October along with a possible conflict in the Middle East both add to the uncertainties that could cause problems for the economy going forward.

In the near term, governments are focused on economic recovery and the growth of their economies, which could lead to an environment of attractive investment opportunities. Over the long term, the uncertainties mentioned earlier could hinder the potential growth. Because of this, Nuveen's investment management teams work hard to balance return and risk with a range of investment strategies. I encourage you to read the following commentary on the management of your fund.

On behalf of the other members of your Fund Board, we look forward to continuing to earn your trust in the months and years ahead.

Sincerely,

William J. Schneider
Chairman of the Nuveen Fund Board
September 23, 2013

Portfolio Managers' Comments

Nuveen Senior Income Fund (NSL)
Nuveen Floating Rate Income Fund (JFR)
Nuveen Floating Rate Income Opportunity Fund (JRO)
Nuveen Short Duration Credit Opportunities Fund (JSD)

The Funds' investment portfolios are managed by Symphony Asset Management, LLC (Symphony), an affiliate of Nuveen Investments. Gunther Stein and Scott Caraher manage NSL, JFR and JRO. JSD is managed by Gunther, Scott and Jenny Rhee. Here they discuss the economic and market conditions, key investment strategies and performance of the Funds for the twelve-month reporting period ended July 31, 2013.

What were the general market conditions and trends during this twelve-month reporting period ended July 31, 2013?

During this reporting period, the U.S. economy's progress toward recovery from recession continued at a moderate pace. The Federal Reserve (Fed) maintained its efforts to improve the overall economic environment by holding the benchmark fed funds rate at the record low level of zero to 0.25% that it established in December 2008. The Fed also continued its monthly purchases of $40 billion of mortgage-backed securities and $45 billion of longer-term Treasury securities in an open-ended effort to bolster growth. At its September 2013 meeting (subsequent to the end of this reporting period), the Fed indicated that downside risks to the economy had diminished since the fall of 2012, but that recent tightening of financial conditions, if sustained, could potentially slow the pace of improvement in the economy and labor market. Consequently, the Fed made no changes to its highly accommodative monetary policies at the September meeting, announcing its decision to wait for additional evidence of sustained economic progress before adjusting the pace of its bond buying program.

As measured by gross domestic product (GDP), the U.S. economy grew at an estimated annualized rate of 1.7% in the second quarter of 2013, compared with 1.1% for the first quarter, continuing the pattern of positive economic growth for the 16th consecutive quarter. The Consumer Price Index (CPI) rose 2.0% year-over-year as of July 2013, while the core CPI (which excludes food and energy) increased 1.7% during the period, staying within the Fed's unofficial objective of 2.0% or lower for this inflation measure. Meanwhile, labor market conditions continued slowly to show signs of improvement, although unemployment remained above the Central Bank's 6.5% target. As of July 2013, the national unemployment rate was 7.4%. The housing market, long a major weak spot in the U.S. economic recovery, also delivered some good news as the average home price in the S&P/Case-Shiller Index of 20 major metropolitan areas rose 12.1% for the twelve months ended June 2013 (most recent data available at the time this report was prepared). The outlook for the U.S. economy, however, continued to be clouded by uncertainty about global financial markets and the

Certain statements in this report are forward-looking statements. Discussions of specific investments are for illustration only and are not intended as recommendations of individual investments. The forward-looking statements and other views expressed herein are those of the portfolio managers as of the date of this report. Actual future results or occurrences may differ significantly from those anticipated in any forward-looking statements and the views expressed herein are subject to change at any time, due to numerous market and other factors. The Funds disclaim any obligation to update publicly or revise any forward-looking statements or views expressed herein.

Ratings shown are the highest rating given by one of the following national rating agencies: Standard & Poor's, Moody's Investors Service, Inc. or Fitch, Inc. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below investment grade ratings. Certain bonds backed by U.S. Government or agency securities are regarded as having an implied rating equal to the rating of such securities. Holdings designated N/R are not rated by these national rating agencies.

outcome of the "fiscal cliff" negotiations. The tax consequences of the fiscal cliff situation, scheduled to become effective in January 2013, were averted through a last minute deal that raised payroll taxes, but left in place a number of tax breaks. Lawmakers postponed and then failed to reach a resolution on $1.2 trillion in spending cuts intended to address the federal budget deficit. As a result, automatic spending cuts (or sequestration) affecting both defense and non-defense programs (excluding Social Security and Medicaid) took effect March 1, 2013, with potential implications for U.S. economic growth over the next decade. In late March 2013, Congress passed legislation that established federal funding levels for the remainder of fiscal 2013, which ends on September 30, 2013, preventing a federal government shutdown. The proposed federal budget for fiscal 2014 remains under debate.

For the majority of the reporting period, generally improving economic data and diminished systemic risk fears were supportive of risk assets in general and fixed income spread sectors specifically. The pressure to find yield continued to provide strong technical underpinnings to the market as investor flows indicated robust demand for fixed income securities during most of the reporting period. The tide quickly turned in the final month of the reporting period, however, triggered by the Fed Chairman's comments that the economic outlook had improved enough to warrant a possible "tapering" of the Central Bank's quantitative easing programs as soon as September of this year, earlier than the market anticipated. In response, Treasury yields rose sharply, while global risk assets, including equities, spread products and growth-sensitive currencies, sold off significantly. The combination of rising yields and a sell-off in risk assets in June was somewhat unusual; the two have generally been negatively correlated over the past several years. The common thread in the markets appeared to be a general "de-risking" by investors based on concerns about the Central Bank's withdrawal of policy stimulus.

While the Fed Chairman's remarks and the subsequent magnitude and speed of the rise in Treasury yields surprised many investors, we believe the overall positioning by the Fed is a positive. As investors adjust their expectations and shift their portfolios to more appropriately position for increasing interest rates, we anticipate loans will hold up on a technical basis and continue to outperform other fixed income instruments on a relative basis.

What strategies were used to manage the Funds during the twelve-month reporting period ended July 31, 2013? How did these strategies influence performance?

NSL, JFR and JRO have similar investment objectives and strategies. Each Fund is designed to seek a high level of current income by primarily investing in a portfolio of adjustable rate, senior secured corporate loans. The Funds also may invest in unsecured senior loans, other debt securities, equity securities and warrants acquired in connection with an investment in senior loans. A significant portion of each Fund's assets may be invested in instruments that, at the time of investment, are rated below investment grade or are unrated but judged by Symphony to be of comparable quality. JSD seeks to provide current income and the potential for capital appreciation. The Fund invests primarily in a blended portfolio of below investment grade adjustable rate corporate debt instruments, including senior secured loans, second lien loans and other adjustable rate corporate debt instruments. The Fund may also make limited tactical investments in other types of debt instruments and may enter into tactical short positions consisting of primarily high yield debt. During the reporting period, the maximum CCC+ and lower rated policy for all four Funds was changed. NSL (originally 10%), JFR (originally 10%), JRO (originally 15%) and JSD (originally 20%) may now invest up to 30% of their managed assets in CCC+ and lower rated credits. The purpose of the change was to increase each Fund's flexibility and the team's ability to take advantage of market opportunities.

How did the Funds perform during this twelve-month reporting period ended July 31, 2013?

The tables in the Performance Overview and Holding Summaries section of this report provide total return performance for each Fund for the one-year, five-year, ten-year and/or since inception periods ended July 31, 2013. For the twelve-month reporting period ended July 31, 2013, the Funds' common share at net asset value (NAV) outperformed both the

Barclays U.S. Aggregate Bond Index and the CSFB Leveraged Loan Index. Loans in general performed well during the reporting period, as the asset class was supported by demand for floating rate products from institutional investors and collateralized loan obligation new issuance.

The Fund's maintained exposure primarily to senior loans during the reporting period which benefitted performance. Exposure consisted of mainly U.S. issuers and was focused on companies that, in general, had high levels of tangible assets, predictable revenue streams, significant market share within their respective industries and positive free cashflow. The term loans and high yield bonds of Clear Channel Communications Inc., a diversified media and entertainment company, continued to be strong performers for the Funds. The loans and bonds traded higher as the company launched an exchange in May 2013 to push out approximately half of their 2016 maturities, offering significantly higher yield in exchange for a longer maturity. The term loans and high yield bonds of Avaya, Inc., an enterprise communications company, were also contributors to the Funds' positive performance as the company reached an agreement with investors to amend and extend its term B-1 loans. We sold our positions in Avaya during the reporting period. On the downside, the Funds were negatively affected by positions in LifeCare Holdings, Inc. because the loans traded down during the reporting period. Also detracting from performance were the loans of Cengage Learning Acquisitions, Inc., a private textbook company, that filed for Chapter 11 bankruptcy protection in July 2013. While the company's results deteriorated quicker than we originally forecasted, we continue to believe the recovery value will be higher than the current valuation. In addition, JSD benefited from short exposures to Kohl's Corporation and Best Buy Co., Inc. Both companies sold off during the fourth quarter of 2012 after reporting disappointing revenue results.

There has been an increased focus on the structure of many senior loans in the market, including LIBOR floors. These are fairly recent developments and worthy of discussion. All of these Funds have owned, or currently own, loans with the LIBOR floor feature. The coupon on most senior loans consists of both LIBOR (usually 90-day U.S. LIBOR) plus a spread. For example, a senior loan might have a coupon structure of "LIBOR plus 400 basis points (bp)" in which the coupon consists of 90-day LIBOR, plus 400bp. Given today's relatively low LIBOR rate, however, many issuers have put in place LIBOR floors to enhance the yield (and satisfy demand from investors) for newly issued loans. LIBOR floors, as the name suggests, put a "floor" on the reference LIBOR rate. LIBOR floors typically range from 150bp to 50bp. A loan with a LIBOR floor might have a structure of "LIBOR + 400bp with a 100bp LIBOR floor." In this example, the effective coupon is 5% (100bp + 400bp). As a result, as LIBOR rises from current levels, the yield on a senior loan with a LIBOR floor will not rise in lockstep until after the reference LIBOR rate exceeds the LIBOR floor. Although many loans have LIBOR floors, the asset class is one of the few that will float when interest rates begin to rise, we believe the senior loan asset class provides fixed income oriented investors with a potential safeguard from a secular rise in interest rates.

For JSD, we also continued to invest in credit default swaps, which were used to provide a benefit if particular bonds' credit quality worsened. The Fund does not hold other securities issued by the issuers referenced under these credit default swap contracts. These contracts had a negligible effect on performance.

Fund Leverage

IMPACT OF THE FUNDS' LEVERAGE STRATEGY ON PERFORMANCE

One important factor impacting the returns of the Funds relative to their benchmarks was the Funds' use of leverage through the use of bank borrowings. The Funds use leverage because their managers believe that, over time, leveraging provides opportunities for additional income and total return for common shareholders. However, use of leverage also can expose common shareholders to additional volatility. For example, as the prices of securities held by a Fund decline, the negative impact of these valuation changes on common share NAV and common shareholder total return is magnified by the use of leverage. Conversely, leverage may enhance common share returns during periods when the prices of securities held by a Fund generally are rising. Leverage had a positive impact on the performance of the Funds over this reporting period. During the period, the Funds continued to invest in interest rate swap contracts to partially fix the interest cost of their leverage. This had a negligible effect on performance during the period.

THE FUNDS' REGULATORY LEVERAGE

Bank Borrowings

As discussed previously, the Funds employ regulatory leverage through the use of bank borrowings. As of July 31, 2013, the Funds have outstanding bank borrowings as shown in the accompanying table.

Refer to Notes to Financial Statements, Note 9—Borrowing Arrangements for further details.

As of July 31, 2013, the Funds' percentages of leverage are shown in the accompanying table.

*  Effective leverage is a Fund's effective economic leverage, and includes both regulatory leverage and the leverage effects of certain derivative and other investments in a Fund's portfolio that increase the Fund's investment exposure. Regulatory leverage consists of preferred shares issued or borrowings of a Fund. Both of these are part of a Fund's capital structure. Regulatory leverage is subject to asset coverage limits set forth in the Investment Company Act of 1940.

Common Share Information

Distribution Information

The following information regarding the Funds' distributions is current as of July 31, 2013. The Funds' distribution levels may vary over time based on each Fund's investment activity and portfolio investment value changes.

During the current reporting period, the Funds' monthly distributions to common shareholders were as shown in the accompanying table.

*  Distribution paid in December 2012.

**  Current distribution rate is based on the Fund's current annualized monthly distribution divided by the Fund's current market price. The Fund's monthly distributions to its shareholders may be comprised of ordinary income, net realized capital gains and, if at the end of the fiscal year the Fund's cumulative net ordinary income and net realized gains are less than the amount of the Fund's distributions, a return of capital for tax purposes.

The Funds employ leverage through the use of bank borrowings. Leverage provides the potential for higher earnings (net investment income), total returns and distributions over time, but also increases the variability of common shareholders' NAV per share in response to changing market conditions.

During certain periods, each Fund may pay dividends at a rate that may be more or less than the amount of net investment income actually earned by the Fund during the period. If a Fund has cumulatively earned more than it has paid in dividends, it holds the excess in reserve as undistributed net investment income (UNII) as part of the Fund's NAV. Conversely, if a Fund has cumulatively paid dividends in excess of earnings, the excess constitutes negative UNII that is likewise reflected in the Fund's NAV. Each Fund will, over time, pay all of its net investment income as dividends to shareholders. As of July 31, 2013, all four Funds had positive UNII balances for tax purposes and negative UNII balances for financial reporting purposes.

Common Share Repurchases

As of July 31, 2013, and since the inception of the Funds' repurchase programs, JFR and JRO have cumulatively repurchased and retired their common shares as shown in the accompanying table. Since the inception of the Funds' repurchase programs, NSL and JSD have not repurchased any of their outstanding common shares.

During the current reporting period, JFR and JRO did not repurchase any of their outstanding common shares.

Common Share Equity Shelf Programs

During the current reporting period, NSL, JFR and JRO filed registration statements with the Securities and Exchange Commission (SEC) authorizing the Funds to issue additional common shares through their ongoing equity shelf programs. NSL filed registration statements with the SEC for 3.2 million and 8.8 million additional common shares during August 2012 and March 2013, respectively. JFR filed a registration statement with the SEC for 12.9 million additional common shares during March 2013. JRO filed registration statements with the SEC for 3.1 million and 8.5 million additional common shares during August 2012 and March 2013, respectively.

JSD filed a registration statement with the SEC authorizing the Fund to issue an additional 1.0 million shares through its initial equity shelf program during February 2013.

Under these equity shelf programs, the Funds, subject to market conditions, may raise additional capital from time to time in varying amounts and offering methods at a net price at or above each Fund's NAV per common share.

During the current reporting period, the Funds sold common shares through their equity shelf programs at a weighted average premium to NAV per common share as shown in the accompanying table.

Other Common Share Information

As of July 31, 2013, and during the current reporting period, the Funds common share prices were trading at a premium/(discount) to their common share NAVs as shown in the accompanying table.

Risk Considerations

Fund shares are not guaranteed or endorsed by any bank or other insured depository institution, and are not federally insured by the Federal Deposit Insurance Corporation. Shares of closed-end funds are subject to investment risks, including the possible loss of principal invested. Past performance is no guarantee of future results.

Investment, Market and Price Risk. An investment in common shares is subject to investment risk, including the possible loss of the entire principal amount that you invest. Your investment in common shares represents an indirect investment in the corporate securities owned by the Funds, which generally trade in the over-the-counter markets. Shares of closed-end investment companies like the Funds frequently trade at a discount to their NAV. Your common shares at any point in time may be worth less than your original investment, even after taking into account the reinvestment of Fund dividends and distributions.

Leverage Risk. The Funds' use of leverage creates the possibility of higher volatility for the Funds' per share NAV, market price and distributions. Leverage risk can be introduced through regulatory leverage (issuing preferred shares or debt borrowings at the Fund level) or through certain derivative investments held in a Fund's portfolio. Leverage typically magnifies the total return of a Fund's portfolio, whether that return is positive or negative. The use of leverage creates an opportunity for increased common share net income, but there is no assurance that a Fund's leveraging strategy will be successful.

Tax Risk. The tax treatment of Fund distributions may be affected by new IRS interpretations of the Internal Revenue Code and future changes in tax laws and regulations.

Issuer Credit Risk. This is the risk that a security in a Fund's portfolio will fail to make dividend or interest payments when due.

Illiquid Securities Risk. This is the risk that a Fund may not be able to sell securities in its portfolio at the time or price desired by the Fund.

Non-Investment Grade or Below-Investment Grade Risk. Investments in securities below investment grade quality are predominantly speculative and subject to greater volatility and risk of default.

Unrated Investment Risk. In determining whether an unrated security is an appropriate investment for a Fund, the manager will consider information from industry sources, as well as its own quantitative and qualitative analysis, in making such a determination. However, such a determination by the manager is not the equivalent of a rating by a rating agency.

Senior Loan Risk. Senior loans, both secured and unsecured, may not be rated by a national rating agency at the time of investment, generally will not be registered with the Securities and Exchange Commission (SEC) and generally will not be listed on a securities exchange. In addition, the amount of public information available with respect to senior loans generally is less extensive than that available for more widely rated, registered and exchange-listed securities.

Risks from Unsecured Adjustable Rate Loans or Insufficient Collateral Securing Adjustable Rate Loans. Some of the adjustable rate loans in which a Fund may invest will be unsecured, thereby increasing the risk of loss to the Fund in the event of issuer default. Other adjustable rate loans may be secured by specific collateral, but there can be no assurance that liquidating this collateral would satisfy a borrower's obligation to the Fund in the event of borrower default, or that such collateral could be readily liquidated under such circumstances.

Derivatives Strategy Risk. Derivative securities, such as calls, puts, warrants, swaps and forwards, carry risks different from, and possibly greater than, the risks associated with the underlying investments.

Interest Rate Risk. Fixed-income securities such as bonds, preferred, convertible and other debt securities will decline in value if market interest rates rise.

Reinvestment Risk. If market interest rates decline, income earned from a Fund's portfolio may be reinvested at rates below that of the original investment that generated the income.

Intentionally Left Blank

Nuveen Senior Income Fund (NSL)

Performance Overview and Holding Summaries as of July 31, 2013

Average Annual Total Returns as of July 31, 2013

Past performance is not predictive of future results. Current performance may be higher or lower than the data shown. Returns do not reflect the deduction of taxes that shareholders may have to pay on Fund distributions or upon the sale of Fund shares. Comparative index return information is provided for the Fund's shares at NAV only. Indexes are not available for direct investment.

Common Share Price Performance — Weekly Closing Price

Portfolio Allocation^1,2

(as a % of total investments)

Top Five Issuers^1,2

(as a % of total long-term investments)

Refer to the Glossary of Terms Used in this Report for further definition of the terms used within this page.

1  Holdings are subject to change.

2  Excluding investments in derivatives.

(as a % of total investments)

Nuveen Floating Rate Income Fund (JFR)

Performance Overview and Holding Summaries as of July 31, 2013

Average Annual Total Returns as of July 31, 2013

Past performance is not predictive of future results. Current performance may be higher or lower than the data shown. Returns do not reflect the deduction of taxes that shareholders may have to pay on Fund distributions or upon the sale of Fund shares. Comparative index return information is provided for the Fund's shares at NAV only. Indexes are not available for direct investment.

Common Share Price Performance — Weekly Closing Price

Portfolio Allocation^2,3

(as a % of total investments)

Top Five Issuers^2,3

(as a % of total long-term investments)

Refer to the Glossary of Terms Used in this Report for further definition of the terms used within this page.

1  Since inception returns are from 3/25/04.

2  Holdings are subject to change.

3  Excluding investments in derivatives.

(as a % of total investments)

Nuveen Floating Rate Income Opportunity Fund (JRO)

Performance Overview and Holding Summaries as of July 31, 2013

Average Annual Total Returns as of July 31, 2013

Past performance is not predictive of future results. Current performance may be higher or lower than the data shown. Returns do not reflect the deduction of taxes that shareholders may have to pay on Fund distributions or upon the sale of Fund shares. Comparative index return information is provided for the Fund's shares at NAV only. Indexes are not available for direct investment.

Common Share Price Performance — Weekly Closing Price

Portfolio Allocation^2,3

(as a % of total long-term investments)

Top Five Issuers^2,3

(as a % of total long-term investments)

Refer to the Glossary of Terms Used in this Report for further definition of the terms used within this page.

1  Since inception returns are from 7/27/04.

2  Holdings are subject to change.

3  Excluding investments in derivatives.

(as a % of total investments)

Nuveen Short Duration Credit Opportunities Fund (JSD)

Performance Overview and Holding Summaries as of July 31, 2013

Average Annual Total Returns as of July 31, 2013

Past performance is not predictive of future results. Current performance may be higher or lower than the data shown. Returns do not reflect the deduction of taxes that shareholders may have to pay on Fund distributions or upon the sale of Fund shares. Comparative index return information is provided for the Fund's shares at NAV only. Indexes are not available for direct investment.

Common Share Price Performance — Weekly Closing Price

Portfolio Allocation^2,3

(as a % of total investments)

Top Five Issuers^2,3

(as a % of total investments)

Refer to the Glossary of Terms Used in this Report for further definition of the terms used within this page.

1  Since inception returns are from 5/25/11.

2  Holdings are subject to change.

3  Excluding investments in derivatives.

(as a % of total investments)

Report of INDEPENDENT REGISTERED

PUBLIC ACCOUNTING FIRM

The Board of Trustees and Shareholders
Nuveen Senior Income Fund
Nuveen Floating Rate Income Fund
Nuveen Floating Rate Income Opportunity Fund
Nuveen Short Duration Credit Opportunities Fund

We have audited the accompanying statements of assets and liabilities, including the portfolios of investments, of Nuveen Senior Income Fund, Nuveen Floating Rate Income Fund, Nuveen Floating Rate Income Opportunity Fund, and Nuveen Short Duration Credit Opportunities Fund (the "Funds") as of July 31, 2013, and the related statements of operations and cash flows for the year then ended, the statements of changes in net assets for each of the two years in the period then ended, and the financial highlights for each of the periods indicated therein. These financial statements and financial highlights are the responsibility of the Funds' management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. We were not engaged to perform an audit of the Funds' internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Funds' internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements and financial highlights, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of July 31, 2013, by correspondence with the custodian, counterparty, selling or agent banks, and brokers or by other appropriate auditing procedures where replies from selling or agent banks and brokers were not received. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial positions of Nuveen Senior Income Fund, Nuveen Floating Rate Income Fund, Nuveen Floating Rate Income Opportunity Fund, and Nuveen Short Duration Credit Opportunities Fund at July 31, 2013, and the results of their operations and their cash flows for the year then ended, the changes in their net assets for each of the two years in the period then ended, and the financial highlights for each of the periods indicated therein, in conformity with U.S. generally accepted accounting principles.

Chicago, Illinois
September 25, 2013

NSL

Nuveen Senior Income Fund

Portfolio of Investments

  July 31, 2013

NSL

Nuveen Senior Income Fund (continued)

Portfolio of Investments July 31, 2013