Item 1. Reports to Stockholders.

Beginning on January 1, 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of the Funds’ annual and semi-annual shareholder reports will no longer be sent 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.

If you have already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive shareholder reports and other communications from the Funds electronically anytime by contacting the financial intermediary (such as a broker-dealer or bank) through which you hold your Fund shares or, if you are a direct investor, by enrolling at www.nuveen.com/e-reports.

You may elect to receive all future shareholder reports in paper free of charge at any time by contacting your financial intermediary or, if you are a direct investor, by calling 800-257-8787 and selecting option #1. Your election to receive reports in paper will apply to all funds held in your account with your financial intermediary or, if you are a direct investor, to all your directly held Nuveen Funds and any other directly held funds within the same group of related investment companies.

Semiannual Report

Life is Complex.

Nuveen makes things e-simple.

It only takes a minute to sign up for e-Reports. Once enrolled, you’ll receive an e-mail as soon as your Nuveen Fund information is ready. No more waiting for delivery by regular mail. Just click on the link within the e-mail to see the report and save it on your computer if you wish.

Free e-Reports right to your email!

www.investordelivery.com

If you receive your Nuveen Fund distributions and statements from your financial advisor or brokerage account.

or

www.nuveen.com/client-access

If you receive your Nuveen Fund distributions and statements directly from Nuveen.

Must be preceded by or accompanied by a prospectus.

NOT FDIC INSURED  MAY LOSE VALUE  NO BANK GUARANTEE

3

Chair’s Letter to Shareholders

4

Portfolio Managers’

Comments

Nuveen High Income Bond Fund

Nuveen Strategic Income Fund

These Funds feature portfolio management by Nuveen Asset Management, LLC (NAM), an affiliate of Nuveen Fund Advisors, LLC, the Funds’ investment adviser. Kevin Lorenz, CFA and Jean C. Lin, CFA, are portfolio managers for the Nuveen High Income Bond Fund. Portfolio managers for the Nuveen Strategic Income Fund include Douglas M. Baker, CFA, Bill Martin, Kevin Lorenz, CFA, Katherine Renfrew and Nicholas Travaglino.

Effective July 31, 2019, Timothy A. Palmer, CFA, is no longer a portfolio manager for the Fund.

In this report, the portfolio management team for the Funds discuss key investment strategies and the Funds’ performance for the six-month reporting period ended December 31, 2019.

What strategies were used to manage the Funds during the six-month reporting period and how did these strategies influence performance?

The Funds continued to employ the same fundamental investment strategies and tactics used previously, although implementation of those strategies depended on the individual characteristics of the portfolios, as well as market conditions. The Funds’ management teams use a highly collaborative, research-driven approach that we believe offers the best opportunity to achieve consistent, superior long-term performance on a risk-adjusted basis across the full range of market environments. During the reporting period, the Funds were generally positioned for an environment of continued moderate economic growth. Nonetheless, during the reporting period we made smaller scaled shifts on an ongoing basis that were geared toward improving each Fund’s profile in response to changing conditions and valuations. These strategic moves are discussed in more detail within each Fund’s section of this report.

Nuveen High Income Bond Fund

The Fund’s Class A Shares at NAV outperformed both the Bloomberg Barclays High Yield 2% Issuer Capped Index and the Lipper Global High Yield Funds Classification Average for the six-month reporting period.

The U.S. economy continued to grow at a modest pace during the reporting period, reflecting continued trade friction and global growth concerns. Consumer spending supported growth, while business spending remained disappointing and manufacturing contracted starting in September. Weak global growth prompted central banks around the world to make a synchronized pivot to monetary stimulus. The Federal Reserve (Fed) cut rates three times during the reporting period in response to the global economic downshift along with trade-related uncertainties in a benign inflation

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; 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.

5

Portfolio Managers’ Comments (continued)

environment. Although businesses remained cautious, global growth stabilized as trade tensions eased, Brexit risk declined and China’s manufacturing sector improved. Financial markets responded positively with credit spreads tightening, equity markets rallying and volatility declining. At the December 2019 meeting, Fed policymakers held rates steady while also signaling that they expect to leave rates unchanged in 2020.

During the reporting period, Treasury yields fell, but more so at the front end of the yield curve driven by three Federal Reserve (Fed) rate cuts. Three-month T-bills ended the reporting period 57 basis points lower at 1.55%, while the yield on the 10-year Treasury fell by only 8 basis points to end at 1.92%. As a result, the Treasury yield curve re-steepened following the year’s earlier inversion, which happens when short-term interest rates are higher than longer-term rates. The three-month to 10-year Treasury spread turned positive for the first time since May 2019. Globally, yields also fell and at one point during the reporting period, more than $14 trillion worth of global bonds were trading with negative yields. Although businesses remained cautious, global growth stabilized as trade tensions eased, Brexit risk declined and China’s manufacturing sector improved. Financial markets responded positively with credit spreads tightening, equity markets rallying and volatility declining.

The high yield market continued to be supported by dovish central banks and stable credit fundamentals, which kept recession at bay. Also, the technical backdrop was strong as capital from around the globe continued to flow into the asset class in the hunt for yield in the ultra-low rate environment. Although earnings momentum moderated in the fourth quarter 2019, the supportive macro backdrop and more favorable business sentiment going into 2020 collapsed market volatility, providing a strong tailwind for valuations in the high yield market. Spreads tightened and revisited their post-crisis tight levels by the end of the reporting period, particularly in the higher quality segment of the market and the high yield asset class produced strong returns. The spread of the Bloomberg Barclays U.S. High Yield Index decreased 41 basis points during the reporting period to end at 336 basis points over Treasuries.

The higher quality tiers of high yield outpaced lower quality bonds during the reporting period as they had since the beginning of the year. However, in the final months of the reporting period, we saw a reversal and more volatile, lower quality credits outperformed higher quality issues within the asset class, despite various sorts of headline risk. The demand for riskier assets was generally aided by improved forward-looking sentiment and the energy sector as oil prices rose. CCC rated credit handily outperformed both the BB and B segments during December 2019. The “risk-on” mentality in the final few months of the reporting period encouraged investors to put idle dollars to work. The increased demand for risk also allowed for high yield issuance to hit record levels as 2019 came to a close.

The Fund experienced strong outperformance and had very few performance detractors given the “risk-on” rally and dampened volatility. The most impactful contributors were related to the Fund’s various credit quality exposures. In particular, performance was enhanced by a significant overweight position in the single B rating category. Results also benefited from an underweight position in C to CCC+ rated bonds versus the benchmark, due to the segment’s underperformance. Additionally, security selection aided results among lower rated credits. Finally, although an underweight to the strongest performing, BB rated segment detracted, our strong security selection more than made up for the shortfall.

The Fund’s allocation to preferred and contingent capital (CoCo) securities was also a modest contributor to results. These securities outperformed all other fixed income sectors due to strong underlying credit fundamentals and relatively modest supply in the face of ongoing investor demand for income. Bank stress test results conducted during 2019 reaffirmed the strength of banks, by far the largest sector within these markets, both inside and outside the U.S. CoCos were further supported by the U.K. election results in December 2019, which eliminated a significant amount of uncertainty surrounding Brexit and its possible carryover issues to other European countries. In addition, the steady decline in interest rates continued to stoke investor demand for higher yielding solutions such as preferred and CoCo securities.

6

At the industry level, security selection was strong among three sectors where the Fund held underweights: communications, consumer cyclicals and consumer non-cyclicals. In the communications sector, the Fund benefited from underweights to satellite service operator Intelsat and Frontier Communications, as well as overweights to Cox Media and Vodafone Group. The consumer cyclical area was also additive due to strong security selection in the cyclical services and home construction areas. Finally, in consumer non-cyclical, positive selection in health care (hospitals) and pharmaceuticals contributed favorably to relative performance.

Among other sectors, the largest individual contributor was an overweight position in CommScope, Inc., a telecommunications infrastructure provider that posted above-consensus earnings following an acquisition that closed in April 2019. Also, the Fund’s lack of exposure to benchmark component McDermott Technology benefited results. The oilfield services company had engineering and construction contracts with massive cost overruns that caused the value of its bonds to plummet.

The Fund had no material detractors to relative performance in terms of sector or credit quality weightings. In fact, given the strong rally in high yield markets, the largest drag on the portfolio came from its holdings in cash and equivalents, which increased slightly during the reporting period.

In terms of individual securities, an overweight in business process automation provider Exela detracted in the technology sector. Bonds suffered losses after the market grew concerned about liquidity and business fundamentals following a recent earnings miss and negative outlook revision. The Fund continues to own Exela. In energy, overweight positions in natural gas pipeline owner and operator Antero Midstream and natural gas exploration and production (E&P) firm Chesapeake Energy modestly detracted. Although commodity prices rebounded during the reporting period, Chesapeake Energy delivered poor results, leading to worries about a potential technical default in the event the company fell out of compliance with leverage covenants. The Fund continues to own Antero Midstream but eliminated its holding in Chesapeake Energy.

During the reporting period, the Fund used credit default swaps to hedge the Fund’s high yield credit exposure. These positions had a negligible impact on performance during the reporting period.

Nuveen Strategic Income Fund

The Fund’s Class A Shares at net asset value (NAV) outperformed the Bloomberg Barclays Aggregate Bond Index and the Lipper Multi-Sector Income Funds Classification Average for the six-month reporting period.

The U.S. economy continued to grow at a modest pace during the reporting period, reflecting continued trade friction and global growth concerns. Consumer spending supported growth, while business spending remained disappointing and manufacturing contracted starting in September. Weak global growth prompted central banks around the world to make a synchronized pivot to monetary stimulus. The Federal Reserve (Fed) cut rates three times during the reporting period in response to the global economic downshift along with trade-related uncertainties in a benign inflation environment. Although businesses remained cautious, global growth stabilized as trade tensions eased, Brexit risk declined and China’s manufacturing sector improved. Financial markets responded positively with credit spreads tightening, equity markets rallying and volatility declining. At the December 2019 meeting, Fed policymakers held rates steady while also signaling that they expect to leave rates unchanged in 2020.

During the reporting period, Treasury yields fell, but more so at the front end of the yield curve driven by the Fed rate cuts. Three-month T-bills ended the reporting period 57 basis points lower at 1.55%, while the yield on the 10-year Treasury fell by only 8 basis points to end at 1.92%. As a result, the Treasury yield curve re-steepened following the year’s earlier inversion, which happens when short-term interest rates are higher than longer-term rates. The three-month to 10-year Treasury spread turned positive for the first time since May 2019. Globally, yields also fell and, at one point during the reporting period, more than $14 trillion worth of global bonds were trading with negative yields.

7

Portfolio Managers’ Comments (continued)

The most significant driver of the Fund’s outperformance was its diversified exposure to credit sectors that offered a significant yield advantage over government sectors. In particular, a healthy allocation to preferred and contingent capital (CoCo) securities during the reporting period provided substantial excess returns. These securities outperformed all other fixed income sectors due to strong underlying credit fundamentals and relatively modest supply in the face of ongoing investor demand for income. Bank stress test results conducted during 2019 reaffirmed the strength of banks, by far the largest sector within these markets, both inside and outside the U.S. CoCos were further supported by the U.K. election results in December 2019, which eliminated a significant amount of uncertainty surrounding Brexit and its possible carryover issues to other European countries. In addition, the steady decline in interest rates continued to stoke investor demand for higher yielding solutions such as preferred and CoCo securities.

Allocations to high yield credit and leveraged loans also significantly aided results. High yield bonds were also among the top performing sectors. The sector was supported by dovish central banks and stable credit fundamentals, which kept recession at bay, while capital from around the globe continued to flow into the asset class in the hunt for yield. Although earnings momentum moderated in the fourth quarter 2019, the supportive macro backdrop and more favorable business sentiment going into 2020 collapsed market volatility, providing a strong tailwind for valuations in the high yield market. Spreads tightened throughout the reporting period. Although risk appetite did pick up later in the reporting period, the higher quality areas of the high yield market still significantly outperformed lower quality bonds for the reporting period as a whole. The Fund benefited from both an overweight to high yield and selection within the sector. An out-of-index allocation to leveraged loans also aided results. Fundamentals remained strong as default activity stayed muted, while the amount of repayments led to a technical tailwind as managers were left with large cash balances to reinvest. Later in the reporting period, the segment benefited from lower new issue volume and less merger and acquisition activity. Because of elevated valuations, we maintained a hedge on high yield exposure, reducing the Fund’s net bond and loan exposure to around 15% by the end of the reporting period.

In addition, the Fund’s performance benefited from a substantial underweight to U.S. Treasury securities. We maintained this underweight in Treasuries given our generally constructive economic view and income focus for the Fund.

The Fund experienced few performance detractors given the period’s “risk-on” rally and dampened volatility based on stabilizing global growth, easing trade tensions and declining Brexit risk. Given this market backdrop, the Fund’s overweight allocations to securitized sectors, including asset-backed securities (ABS) and commercial mortgage-backed securities (CMBS), were somewhat of a drag on performance because these sectors underperformed relative to corporate credit. However, the Fund’s exposure to ABS and CMBS did not detract from absolute returns.

Interest rate positioning was the only detractor of note given the move lower in rates. (Bond prices move in the opposite direction of rates.) We had positioned the Fund with a moderately shorter duration relative to its benchmark during the reporting period, which lessened its interest rate sensitivity. Although we extended the duration modestly as the reporting period progressed, it still remained short versus the benchmark and was not enough to offset the full impact from falling rates.

During the reporting period, we also continued to utilize various derivative instruments. We utilized U.S. Treasury futures and Eurodollar futures as part of an overall portfolio construction strategy to manage portfolio duration and yield curve exposure and selected foreign bond futures to actively manage exposure to those markets. These positions had a positive impact on performance during the reporting period.

In addition, we entered into credit default swaps as a way to lower overall high yield exposure. The effect of these activities on performance was negligible during the reporting period.

8

Risk Considerations

and Dividend Information

Risk Considerations

Nuveen High Income Bond 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, call risk, derivatives risk, income risk, and other investment company 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.

Nuveen Strategic 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, call risk, derivatives risk, dollar roll transaction 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 Fund gains additional exposure to currency rates, and therefore to the risk of currency fluctuation, through investment in foreign currency contracts. The risks of foreign investments are magnified in emerging markets. Asset-backed and mortgage-backed securities are subject to additional risks such as prepayment risk, liquidity risk, default risk and adverse economic developments.

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.

9

Fund Performance

and Expense Ratios

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

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. Returns at net asset value (NAV) would be lower if the sales charge were included.

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 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.

The expense ratios shown reflect total operating expenses (before fee waivers and/or expense reimbursements, if any) as shown in the most recent prospectus. The expense ratios include management fees and other fees and expenses.

10

Fund Performance and Expense Ratios (continued)

Nuveen High Income Bond 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 the Glossary of Terms Used in this Report for definitions of terms used within this section.

11

Fund Performance and Expense Ratios (continued)

Nuveen Strategic 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 the Glossary of Terms Used in this Report for definitions of terms used within this section.

12

Yields    as of December 31, 2019

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.

13

Holding Summaries    as of December 31, 2019

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.

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