Strategy. In seeking a high level of current income, the Fund will invest, under normal circumstances, at least 80% of its net assets in securities issued or guaranteed by the U.S. government or by its agencies, instrumentalities or sponsored enterprises and repurchase agreements relating to such securities. These may include: ? U.S. Treasury bills, notes and bonds; ? Obligations of the U.S. government or its agencies, instrumentalities or sponsored enterprises, including obligations that are issued by private issuers that are guaranteed as to principal and interest by the U.S. government, its agencies or instrumentalities; ? Mortgage-related securities issued or guaranteed by the U.S. government or by its agencies, instrumentalities or sponsored enterprises, including U.S. agency mortgage-backed pass-through securities (MBS) that may … Show more… In seeking a high level of current income, the Fund will invest, under normal circumstances, at least 80% of its net assets in securities issued or guaranteed by the U.S. government or by its agencies, instrumentalities or sponsored enterprises and repurchase agreements relating to such securities. These may include: ? U.S. Treasury bills, notes and bonds; ? Obligations of the U.S. government or its agencies, instrumentalities or sponsored enterprises, including obligations that are issued by private issuers that are guaranteed as to principal and interest by the U.S. government, its agencies or instrumentalities; ? Mortgage-related securities issued or guaranteed by the U.S. government or by its agencies, instrumentalities or sponsored enterprises, including U.S. agency mortgage-backed pass-through securities (MBS) that may not be backed by the full faith and credit of the U.S. government; ? Stripped securities evidencing ownership of future interest or principal payments on obligations of the U.S. government or its agencies, instrumentalities or sponsored enterprises; ? Obligations of supranational organizations (such as the World Bank); and ? Inflation-indexed securities. The Fund may also seek to obtain all or a portion of the Funds exposure to MBS by investing in shares of one or more affiliated or unaffiliated investment companies, including exchange-traded funds (ETFs). The Fund may seek to obtain exposure to MBS through to-be-announced (TBA) transactions. Most transactions in MBS occur through TBA transactions, which are standardized contracts for future delivery in which the exact mortgage pools to be delivered are not specified until a few days prior to settlement. In buying and selling securities for the Fund, NTI uses a relative value approach. This approach involves an analysis of general economic and market conditions. It also involves the use of models that analyze and compare expected returns and assumed risks. Under the relative value approach, NTI will emphasize particular securities and types of securities (such as treasury, agency, asset-backed and mortgage-related securities) that the team believes will provide a favorable return in light of these risks. The Funds dollar-weighted average maturity, under normal circumstances, will range between one and ten years. The Fund may also make significant investments in securities issued by U.S. government-sponsored enterprises. Obligations issued by U.S. government-sponsored enterprises are neither issued nor guaranteed by the U.S. Treasury and therefore are not backed by the full faith and credit of the United States. NTI may engage in active trading, and will not consider portfolio turnover a limiting factor in making decisions for the Fund. In seeking to achieve its investment objective, the Fund may invest in U.S. Treasury futures, which are considered to be derivative instruments, for various purposes, including to manage duration, credit and interest rate risks, and for cash management. Show less