Strategic Income Fund

The Thornburg Strategic Income Fund, (the "Fund") did not declare capital gain dividends during 2017.

For the 2017 calendar year, 5.43% of the dividends paid from tax basis ordinary income (box 1a of Form 1099-DIV) qualify as qualified dividend income ("QDI") (box 1b of Form 1099-DIV) for the reduced tax rate under the American Taxpayers Relief Act of 2012.

2.43% of the ordinary income dividends paid by the Fund for 2017 (box 1a of Form 1099-DIV) qualify for the corporate dividends received deduction.

Tax rules are complex. Please consult your tax advisor.

Important Information
Before investing, carefully consider the Fund’s investment goals, risks, charges, and expenses. For a prospectus or summary prospectus containing this and other information, contact your financial advisor or visit Read them carefully before investing.

Investments carry risks, including possible loss of principal. Portfolios investing in bonds have the same interest rate, inflation, and credit risks that are associated with the underlying bonds. The value of bonds will fluctuate relative to changes in interest rates, decreasing when interest rates rise. This effect is more pronounced for longer-term bonds. Unlike bonds, bond funds have ongoing fees and expenses. Investments in lower rated and unrated bonds may be more sensitive to default, downgrades, and market volatility; these investments may also be less liquid than higher rated bonds. Investments in derivatives are subject to the risks associated with the securities or other assets underlying the pool of securities, including illiquidity and difficulty in valuation. Investments in equity securities are subject to additional risks, such as greater market fluctuations. Additional risks may be associated with investments outside the United States, especially in emerging markets, including currency fluctuations, illiquidity, volatility, and political and economic risks. Investments in the Fund are not FDIC insured, nor are they bank deposits or guaranteed by a bank or any other entity.

Thornburg mutual funds are distributed by Thornburg Securities Corporation.

Thornburg Investment Management, Inc. mutual funds are sold through investment professionals including investment advisors, brokerage firms, bank trust departments, trust companies and certain other financial intermediaries. Thornburg Securities Corporation (TSC) does not act as broker of record for investors.