As permitted by regulations adopted by the Securities and Exchange Commission, paper copies of the Funds’ annual and semiannual shareholder reports will not be sent to you by mail unless you specifically request paper copies of the reports. Instead, the reports will be made available on the Funds’ website (www.nuveen.com), and you will be notified by mail each time a report is posted and provided with a website link to access the report.

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Annual Report

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3

Chair’s Letter to Shareholders

4

Portfolio Managers’ Comments

Nuveen High Yield Income Fund

Nuveen Floating Rate Income Fund

The Funds’ are sub-advised by Nuveen Asset Management, LLC (NAM), an affiliate of Nuveen Fund Advisors, LLC, the Funds’ investment adviser (the “Adviser”). On December 31, 2020, the Funds’ previous sub-adviser, Symphony Asset Management, LLC (“Symphony”), also an affiliate of the Adviser, was merged with and into NAM (the “Reorganization”). Effective as of the date of the Reorganization, NAM assumed the portfolio management responsibilities for the Funds’ investment portfolio and, as previously approved by the Fund’s Board of Trustees, the Funds’ entered into an amended and restated sub-advisory agreement with NAM, the terms of which were substantially identical to the prior subadvisory agreement with Symphony. Portfolio Managers Scott Caraher and Jean C. Lin, CFA, continue to oversee the investments of the Nuveen High Yield Income Fund. Portfolio Managers Scott Caraher and Kevin Lorenz, CFA, continue to oversee the investments of the Nuveen Floating Rate Income Fund.

Here the portfolio management team discusses economic and market conditions, key investment strategies and the Funds’ performance for the twelve-month reporting period ended September 30, 2021. For more information on the Funds’ investment objectives and policies, please refer to the Funds’ prospectus.

What factors affected the economy and the markets during the twelve-month annual reporting period ended September 30, 2021?

Supported by massive fiscal and monetary stimulus and economic reopening, the U.S. economy rebounded more quickly than expected from the deep downturn caused by the COVID-19 crisis and containment measures. The federal government’s relief measures have totaled approximately $5.3 trillion across six aid packages, which included direct payments to individuals and families, expanded unemployment insurance, loans to large and small businesses, funding for hospitals and health agencies, state and local governments, education and public health/vaccinations. Additionally, after the close of this reporting period, Congress approved a $1 trillion infrastructure and jobs plan in November 2021, which funds improvements to roads/bridges, broadband internet, airports and ports, and water and power systems. The U.S. Federal Reserve (Fed) has maintained short-term interest rates near zero and enacted credit facilities to help keep the financial system stable, lowering borrowing costs for businesses and individuals.

By the start of this reporting period, markets had largely stabilized from the initial shock of the health crisis. In March 2020, equity and commodity markets sold off and safe-haven assets rallied as countries initiated quarantines, restricted travel and shuttered factories and businesses, while an ill-timed oil price war between the Organization of the Petroleum Exporting Countries (OPEC) and non-OPEC member Russia amplified price volatility. In late 2020, the announcement of high efficacy rates in several COVID-19 vaccine trials, followed by regulatory authorizations and public vaccination drives across Western countries, improved the outlook for 2021, which contributed to risk-on sentiment in the markets. The positive sentiment was realized during the first half of 2021 as U.S. gross domestic product (GDP) expanded at an annualized rate of 6.3% in the first quarter of 2021 and 6.7% in the second quarter of

This material is not intended to be a recommendation or investment advice, does not constitute a solicitation to buy, sell or hold a security or an investment strategy and is not provided in a fiduciary capacity. The information provided does not take into account the specific objectives or circumstances of any particular investor, or suggest any specific course of action. Investment decisions should be made based on an investor’s objectives and circumstances and in consultation with his or her advisors.

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.

For financial reporting purposes, the ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc. (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A and BBB are investment grade ratings, while BB, B, CCC, CC, C and D are below investment grade ratings. Holdings designated N/R are not rated by these national rating agencies.

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

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Portfolio Managers’ Comments (continued)

2021. However, economic growth slowed considerably in the third quarter of 2021 to a 2.0% annualized rate, dampened by the spread of the COVID-19 delta variant and constricted supply chains, according to the “advance” estimate released by the Bureau of Economic Analysis.

Although supply bottlenecks, labor shortages and higher cost inflation have weighed on economic growth in the short term, consumer demand remains strong and COVID-19 cases have fallen from recent peaks. Given the U.S. economy’s progress, the Fed began signaling a timeline for tapering pandemic monetary support by reducing its monthly bond purchases (which was announced at the November 2021 policy meeting, after the close of this reporting period), as well as suggested interest rate normalization that could start later in 2022. In addition to monetary policy, markets remained concerned about the political gridlock over raising the debt ceiling – the amount the U.S. government is allowed to borrow. (After the close of this reporting period, the government enacted a temporary increase to the debt ceiling, but Congress will need to revisit the issue in December 2021.)

During the reporting period, the high yield bond market, as represented by the ICE BofA U.S. High Yield Index, returned 11.5%. Within the high yield bond asset class, prices advanced across industries and the credit spectrum. Lower rated bonds led the way during the reporting period, with CCC-rated bonds outperforming BB and B-rated bonds. As spreads narrowed, the index ended the reporting period with both its yield-to-worst and option-adjusted spread (OAS) at multi-year lows. High yield bond credit fundamentals were sound, bolstered by generally healthy consumer and corporate balance sheets.

In terms of senior loans, relatively stable conditions prevailed in the reporting period led by improvement in the fundamentals for the asset class. In addition, loans benefited from strong demand throughout the first nine months of 2021. During that stretch, retail mutual funds and exchange-traded funds (ETFs) garnered $34 billion of inflows as the institutional collateralized loan obligations (CLO) market continued to produce a historic amount of net demand ($122 billion) for loans. The total inflows climbed toward the end of the reporting period as volatility picked up in the U.S. Treasury market. With their floating rate coupon structures, loans tend to see an increase in retail flows during times of rising interest rates and duration-driven volatility.

Nuveen High Yield Income Fund

What strategies were used to manage the Fund during the twelve-month reporting period ended September 30, 2021?

The investment objective of the Fund is to seek current income and capital appreciation by investing primarily in debt instruments such as bonds, loans and convertible securities, a substantial portion of which may be rated below investment grade or, if unrated, of comparable quality. Nuveen Asset Management (NAM) bases its investment process on fundamental, bottom-up credit analysis. Analysts assess sector dynamics, company business models and asset quality. Specific recommendations are based on an analysis of the relative value of the various types of debt within a company’s capital structure. Inherent in the credit analysis process is the evaluation of potential upside and downside to any credit. As such, NAM concentrates its efforts on sectors where there is sufficient transparency to assess the downside risk and where firms have assets to support meaningful recovery in case of default.

How did the Fund perform during the twelve-month reporting period ended September 30, 2021?

For the twelve-month reporting period ended September 30, 2021, the Fund outperformed the ICE BofA U.S. High Yield Index. For purposes of this Performance Commentary, references to relative performance are in comparison to the ICE BofA U.S. High Yield Index.

For the reporting period, outperformance for the Fund was driven by a tactical allocation to, and positive security selection within, senior loans. On a sector basis, favorable security selection in communication services, consumer discretionary and consumer staples contributed to relative performance. Regarding individual holdings, the loans of automotive and specialty LED light producer Lumileds performed well over the reporting period given improved earnings. The Fund sold the position as the loans appreciated during the reporting period. In addition, loans issued by oil and gas E&P (exploration and production) services provider Fieldwood Energy, LLC rallied as oil prices rose and the company emerged from bankruptcy. The Fund continues to hold the loans of Quarternorth Energy (formerly known as Fieldwood Energy). Lastly, the post-reorganization equity of broadcast company iHeartMedia, Inc. benefited from increased advertising revenue as vaccine optimism improved the U.S. economic outlook. The Fund opportunistically sold the iHeartMedia equity holdings amid rising share prices during the reporting period.

6

Partially offsetting some of the portfolio’s positive relative performance was an underweight in the energy sector. Given the rally in oil prices and overall risk-on sentiment that prevailed during the reporting period, the underweight to lower quality oil field services and midstream issuers detracted from the Fund’s relative returns. Unfavorable security selection within the industrials sector detracted from relative results as well.

Nuveen Floating Rate Income Fund

What strategies were used to manage the Fund during the twelve-month reporting period ended September 30, 2021?

The principal investment objective of the Fund is to seek a high level of current income, and secondarily capital appreciation, by investing primarily in floating rate loans and other floating rate securities, a substantial portion of which will be rated below investment grade. Nuveen Asset Management (NAM) bases its investment process on fundamental, bottom-up credit analysis. Analysts assess sector dynamics, company business models and asset quality. Specific recommendations are based on an analysis of the relative value of the various types of debt within a company’s capital structure. Inherent in the credit analysis process is the evaluation of potential upside and downside to any credit. As such, NAM concentrates its efforts on sectors where there is sufficient transparency to assess the downside risk and where firms have assets to support meaningful recovery in case of default.

How did the Fund perform during the twelve-month reporting period ended September 30, 2021?

For the twelve-month reporting period ended September 30, 2021, the Fund outperformed the Credit Suisse Leveraged Loan Index. For purposes of this Performance Commentary, references to relative performance are in comparison to the Credit Suisse Leveraged Loan Index.

For the reporting period, outperformance for the Fund was driven largely by strong security selection in the loan portfolio, including selection within energy and media and entertainment. The outperformance in the energy sector was led by the loans issued by oil and gas E&P (exploration and production) services provider Fieldwood Energy, LLC, which rallied as oil prices rose, and the company emerged from bankruptcy. The Fund continues to maintain exposure to Quarternorth Energy (formerly known as Fieldwood Energy). Additionally, the Fund’s out of benchmark allocation to equities received from reorganizations contributed to relative performance during the reporting period. In particular, the post-reorganization equity of E&P company California Resources traded higher during the reporting period alongside higher oil prices and earnings. The Fund continues to maintain exposure to California Resources.

Offsetting some of the portfolio’s positive relative performance was an underweight in the lower rated segment of the senior loan market as lower quality assets generally outperformed during the reporting period. In addition, exposure to Diamond Sports LLC, a communication and media services company, detracted from performance. The company has experienced pressure around potential restructuring talks and disappointing earnings during the reporting period. Lastly, Endo Health Solutions, Inc. hurt performance during the reporting period as the issuer faces continued costs from opioid lawsuits. The Fund continues to maintain exposure to Diamond Sports and Endo Health Solutions.

7

Risk Considerations and Dividend Information

Risk Considerations

Nuveen High Yield Income Fund

Mutual fund investing involves risk; principal loss is possible. There is no guarantee the Fund’s investment objectives will be achieved. Investments in below investment grade or high yield securities are subject to liquidity risk and heightened credit risk. Credit risk arises from an issuer’s ability to make interest and principal payments when due, as well as the prices of bonds declining when an issuer’s credit quality is expected to deteriorate. The Fund is subject to interest rate risk; as interest rates rise, bond prices fall. This Fund is subject to the risks of investing in loans, including loan settlement risk due to the lack of established settlement standards or remedies for failure to settle and covenant lite loan risk, which is the risk that loans with limited restrictive covenants on borrowers may weaken the Fund’s ability to access collateral securing the loan and enforce its rights as a lender. Non-U.S. investments involve risks such as currency fluctuation, political and economic instability, lack of liquidity and differing legal and accounting standards. These and other risk considerations, such as active management, call, derivatives, income, and unrated securities risks, are described in detail in the Fund’s prospectus.

Nuveen Floating Rate Income Fund

Mutual fund investing involves risk; principal loss is possible. Debt or fixed income securities such as those held by the Fund, are subject to market risk, credit risk, interest rate risk, derivatives risk, liquidity risk, and income risk. As interest rates rise, bond prices fall. Below investment grade or high yield debt securities are subject to liquidity risk and heightened credit risk. Foreign investments involve additional risks, including currency fluctuation, political and economic instability, lack of liquidity and differing legal and accounting standards. The value of the Fund’s convertible securities may decline in response to such factors as rising interest rates and fluctuations in the market price of the underlying securities. This Fund is subject to loan settlement risk due to the lack of established settlement standards or remedies for failure to settle.

Dividend Information

Each Fund seeks to pay regular monthly dividends out of its net investment income at a rate that reflects its past and projected net income performance. To permit each Fund to maintain a more stable monthly dividend, the Fund may pay dividends at a rate that may be more or less than the amount of net income actually earned by the Fund during the period. Distributions to shareholders are determined on a tax basis, which may differ from amounts recorded in the accounting records. In instances where the monthly dividend exceeds the earned net investment income, the Fund would report a negative undistributed net ordinary income. Refer to Note 6 – Income Tax Information for additional information regarding the amounts of undistributed net ordinary income and undistributed net long-term capital gains and the character of the actual distributions paid by the Fund during the period.

All monthly dividends paid by each Fund during the current reporting period were paid from net investment income. If a portion of the Fund’s monthly distributions is sourced or comprised of elements other than net investment income, including capital gains and/or a return of capital, shareholders will be notified of those sources. For financial reporting purposes, the per share amounts of each Fund’s distributions for the reporting period are presented in this report’s Financial Highlights. For income tax purposes, distribution information for each Fund as of its most recent tax year end is presented in Note 6 – Income Tax Information within the Notes to Financial Statements of this report.

8

Fund Performance and Expense Ratios

The Fund Performance and Expense Ratios for each Fund are shown within this section of the report.

Fund Performance

Returns quoted represent past performance, which is no guarantee of future results. Investment returns and principal value will fluctuate so that when shares are redeemed, they may be worth more or less than their original cost. Current performance may be higher or lower than the performance shown.

Total returns for a period of less than one year are not annualized (i.e. cumulative returns). Since inception returns are shown for share classes that have less than 10-years of performance. Returns at net asset value (NAV) would be lower if the sales charge were included. Returns assume reinvestment of dividends and capital gains. For performance, current to the most recent month-end visit nuveen.com or call (800) 257-8787.

Returns do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption of Fund shares.

Returns may reflect fee waivers and/or expense reimbursements by the investment adviser during the periods presented. If any such waivers and/or reimbursements had not been in place, returns would have been reduced. See Notes to Financial Statements, Note 7—Management Fees and Other Transactions with Affiliates for more information.

Returns reflect differences in sales charges and expenses, which are primarily differences in distribution and service fees, and assume reinvestment of dividends and capital gains.

Comparative index and Lipper return information is provided for Class A Shares at NAV only.

Expense Ratios

The expense ratios shown are as of the Fund’s most recent prospectus. The expense ratios shown reflect total operating expenses (before fee waivers and/or expense reimbursements, if any). The expense ratios include management fees and other fees and expenses. Refer to the Financial Highlights later in this report for the Fund’s expense ratios as of the end of the reporting period.

9

Fund Performance and Expense Ratios (continued)

Nuveen High Yield Income Fund

Refer to the first page of this Fund Performance and Expense Ratios section for further explanation of the information included within this section. Refer to Glossary of Terms Used in this Report for definitions of terms used within this section.

10

Nuveen High Yield Income Fund

Growth of an Assumed $10,000 Investment as of September 30, 2021 – Class A Shares

The graphs do not reflect the deduction of taxes that a shareholder may pay on Fund distributions or the redemption of Fund shares.

11

Fund Performance and Expense Ratios (continued)

Nuveen Floating Rate Income Fund

Refer to the first page of this Fund Performance and Expense Ratios section for further explanation of the information included within this section. Refer to Glossary of Terms Used in this Report for definitions of terms used in this section.

12

Nuveen Floating Rate Income Fund

Growth of an Assumed $10,000 Investment as of September 30, 2021 – Class A Shares

The graphs do not reflect the deduction of taxes that a shareholder may pay on Fund distributions or the redemption of Fund shares.

13

Yields    as of September 30, 2021

Dividend Yield is the most recent dividend per share (annualized) divided by the offering price per share.

The SEC 30-Day Yield is a standardized measure of a Fund’s yield that accounts for the future amortization of premiums or discounts of bonds held in the fund’s portfolio. The SEC 30-Day Yield is computed under an SEC standardized formula and is based on the maximum offer price per share. Subsidized yields reflect fee waivers and/or expense reimbursements from the investment adviser during the period. If any such waivers and/or reimbursements had not been in place, yields would have been reduced. Unsubsidized yields do not reflect waivers and/or reimbursements from the investment adviser during the period. If the fund did not receive a fee waiver/expense reimbursement during the period under its most recent agreement, subsidized and unsubsidized yields will be equal. Refer to the Notes to Financial Statements, Note 7 – Management Fees and Other Transactions with Affiliates for further details on the investment adviser’s most recent agreement with the Fund to waive fees and/or reimburse expenses, where applicable. Dividend Yield may differ from the SEC 30-Day Yield because the fund may be paying out more or less than it is earning and it may not include the effect of amortization of bond premium or discount.

14

Holding Summaries    as of September 30, 2021

This data relates to the securities held in each Fund’s portfolio of investments as of the end of this reporting period. It should not be construed as a measure of performance for the Fund itself. Holdings are subject to change.

For financial reporting purposes, the ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s, Moody’s Investors Service, Inc. or Fitch, Inc. This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. 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. Holdings designated N/R are not rated by these national rating agencies.