Performance data shown represents past performance and is no guarantee of future results. Investment return and principal value will fluctuate so shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than quoted.

The maximum sales charge for the equity funds’ A shares is 4.50%. B shares carry a contingent deferred sales charge (CDSC), if redeemed within a year, of 5.00%; within two years, 4.25%; within three years, 3.50%; within four years, 2.75%; within five years, 2.00%; within six years, 1.25%, within seven years, 0.50%. There is no charge for redemption within the eighth year. C shares include a 1% contingent deferred sales charge (CDSC) for the first year only. There is no up-front sales charge for class I or R shares.

Prior to inception of class I shares, performance is calculated from actual returns of the class A shares adjusted for the lower Institutional expenses.

Prior to inception of the Retirement shares, the performance includes actual returns of class A Shares adjusted for class R expenses. After inception of each Retirement share class, actual class R performance was used.

Returns are annualized for periods greater than one year.

Thornburg Investment Income Builder Fund‘s Blended Index is composed of 25% Barclays U.S. Aggregate Bond Index and 75% MSCI World Index, rebalanced monthly.

*The Fund may invest in shares of companies through initial public offerings (IPOs). IPOs have the potential to produce substantial gains and there is no assurance that the Fund will have continued access to profitable IPOs. As Fund assets grow, the impact of IPO investments on performance may decline.

Performance data shown represents past performance and is no guarantee of future results. Investment return and principal value will fluctuate so shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than quoted.

The maximum sales charge for the Strategic Income Fund’s A shares is 4.50%. C shares include a 1% contingent deferred sales charge (CDSC) for the first year only. The maximum sales charge for the limited-term and low-duration bond funds’ A shares is 1.50%. C shares include a 0.50% CDSC for the first year only. The maximum sales charge for the Strategic Municipal Income and intermediate-term bond funds’ A shares is 2.00%. C shares include a 0.60% CDSC for the first year only. B shares carry a CDSC, if redeemed within a year, of 5.00%; within two years, 4.25%; within three years, 3.50%; within four years, 2.75%; within five years, 2.00%; within six years, 1.25%, within seven years, 0.50%. There is no charge for redemption within the eighth year. There is no up-front sales charge for class D, I or R shares.

Prior to inception of the Retirement shares, the performance includes actual returns of class A Shares adjusted for class R expenses. After inception of each Retirement share class, actual class R performance was used.

Returns are annualized for periods greater than one year.

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 our literature center. Read them carefully before investing.

Thornburg Investment Management and/or Thornburg Securities Corporation have contractually agreed to waive fees and reimburse expenses through at least February 1, 2016, for some of the share classes; these are reflected in the net expense ratio. For more detailed information on fund expenses and waivers/reimbursements, please see the fund’s prospectus.

Investments in the Funds carry risks, including possible loss of principal. Special 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 small capitalization companies may increase the risk of greater price fluctuations. Funds investing in bonds have the same interest rate, inflation, and credit risks that are associated with the underlying bonds. The principal 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 mortgage backed securities (MBS) may bear additional risk. 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 the Funds are not FDIC insured, nor are they deposits of or guaranteed by a bank or any other entity.

The performance of any index is not indicative of the performance of any particular investment. Unless otherwise noted, index returns reflect the reinvestment of income dividends and capital gains, if any, but do not reflect fees, brokerage commissions or other expenses of investing. Investors may not make direct investments into any index.

As of August 1, 2009, Thornburg Investment Management no longer offers Class B Shares. See the current prospectus for more information.

Class I shares may not be available to all investors. Minimum investments for the I share class may be higher than those for other classes.

Class R shares are limited to retirement platforms only.

Please see our glossary for a definition of terms.

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.