Strategy. Thornburg Investment Management, Inc. (Thornburg) actively manages the Funds portfolio in pursuing the Funds investment goal. Under normal conditions, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in debt obligations. The Fund may invest up to 25% of its net assets, plus the amount of any borrowings for investment purposes, in debt obligations which, at the time of purchase, are rated by a nationally recognized statistical rating organization as below investment grade (sometimes called junk bonds or high yield bonds) or, if unrated, are issued by obligors which Thornburg determines to have comparable below investment grade obligations outstanding or to be comparable to obligors with outstanding below investment grade … Show more… Thornburg Investment Management, Inc. (Thornburg) actively manages the Funds portfolio in pursuing the Funds investment goal. Under normal conditions, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in debt obligations. The Fund may invest up to 25% of its net assets, plus the amount of any borrowings for investment purposes, in debt obligations which, at the time of purchase, are rated by a nationally recognized statistical rating organization as below investment grade (sometimes called junk bonds or high yield bonds) or, if unrated, are issued by obligors which Thornburg determines to have comparable below investment grade obligations outstanding or to be comparable to obligors with outstanding below investment grade obligations. The Fund may not, at the time of purchase, invest more than 25% of its net assets, plus the amount of any borrowings for investment purposes, in debt obligations denominated in non-U.S. currencies, but this limitation does not apply to debt obligations issued by foreign issuers and denominated in U.S. dollars. Additionally, the Fund may not, at the time of purchase, invest more than 15% of its net assets, plus the amount of any borrowings for investment purposes, in debt obligations issued by issuers in emerging markets, also known as developing countries. There is no limitation on the duration or maturity of any specific debt obligation the Fund may purchase. The Fund will, however, generally seek to maintain a portfolio of investments with a dollar-weighted average duration that falls within two years of the dollar-weighted average duration of the Funds benchmark index, the Bloomberg U.S. Aggregate Bond Index. Duration is a measure of estimated sensitivity to interest rate changes, and a debt obligation or a portfolio of obligations with a higher duration will typically be more sensitive to interest rate changes than an obligation or a portfolio with a lower duration. Duration is commonly expressed as a number, which is the expected percentage change in an obligations price upon a 1% change in interest rates. For example, an obligation with a duration of 0.5 would be expected to change in price by approximately 0.5% in response to a 1% change in interest rates. While the Fund may invest in debt obligations of any type, the Fund will invest principally in the following types of debt obligations: corporate debt obligations from domestic and foreign issuers of any market capitalization; obligations issued or guaranteed by U.S. and non-U.S. governments and their agencies or instrumentalities; and mortgage-backed and asset-backed securities, including residential or commercial mortgage-backed securities, or collateralized mortgage obligations, issued by agencies of the U.S. government or issued by private entities. Each of the Funds investments is determined by individual issuer and industry analysis, including Thornburgs evaluation of domestic and international economic developments, outlooks for securities markets, interest rates and inflation, and the supply and demand for debt obligations. The Fund may also invest in futures contracts, options, swaps, and forward contracts to hedge against the decline in the value of certain of the Funds investments, to manage portfolio duration, or to enhance the Funds investment returns. The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolios average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investments issuer or changes in overall market conditions, or if, in Thornburgs opinion, the investment no longer serves to achieve the Funds investment goals. Because the Fund seeks to maximize total return while also preserving capital, the Fund may not always obtain the highest yields available. The Funds policy of investing at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in debt obligations may be changed by the Funds Trustees without a shareholder vote upon 60 days notice to shareholders. Show less