Strategy. To pursue its goal, the fund normally invests at least 80% of its net assets, plus any borrowings for investment purposes, in U.S. dollar-denominated fixed-income securities that provide income exempt from federal personal income tax (municipal bonds). Municipal bonds are debt securities or other obligations issued by states, territories and possessions of the United States and the District of Columbia and their political subdivisions, agencies and instrumentalities, or multistate agencies and authorities. While the fund typically invests in a diversified portfolio of municipal bonds, it may invest up to 20% of its net assets in taxable fixed-income securities, including taxable municipal bonds and non-U.S. dollar-denominated foreign debt securities such as Brady bonds and sovereign debt obligations. The fund invests at … Show more… To pursue its goal, the fund normally invests at least 80% of its net assets, plus any borrowings for investment purposes, in U.S. dollar-denominated fixed-income securities that provide income exempt from federal personal income tax (municipal bonds). Municipal bonds are debt securities or other obligations issued by states, territories and possessions of the United States and the District of Columbia and their political subdivisions, agencies and instrumentalities, or multistate agencies and authorities. While the fund typically invests in a diversified portfolio of municipal bonds, it may invest up to 20% of its net assets in taxable fixed-income securities, including taxable municipal bonds and non-U.S. dollar-denominated foreign debt securities such as Brady bonds and sovereign debt obligations. The fund invests at least 50% of its net assets in fixed-income securities that are rated investment grade (i.e., Baa/BBB or higher) or are the unrated equivalent as determined by the fund's sub-adviser, Insight North America LLC (INA), an affiliate of BNY Mellon Investment Adviser, Inc. (BNYIA). To seek additional yield, the fund may invest up to 50% of its net assets in fixed-income securities that are rated below investment grade ("high yield" or "junk" bonds) or are the unrated equivalent as determined by the fund's sub-adviser. The fund may invest in bonds of any maturity or duration and does not expect to target any specific range of maturity or duration. The dollar-weighted average maturity of the fund's portfolio will vary from time to time depending on the portfolio manager's views on the direction of interest rates. A bond's maturity is the length of time until the principal must be fully repaid with interest. Dollar-weighted average maturity is an average of the stated maturities of the securities held by the fund, based on their dollar-weighted proportions in the fund. Duration is an indication of an investment's "interest rate risk," or how sensitive a bond or the fund's portfolio may be to changes in interest rates. Although the fund seeks to provide income exempt from federal income tax, income from some of the fund's holdings may be subject to the federal alternative minimum tax. The fund's sub-adviser seeks to deliver value added excess returns ("alpha") by applying an investment approach designed to identify and exploit relative value opportunities within the municipal bond market and other fixed-income markets. The fund typically sells a security when the fund's sub-adviser believes that there has been a negative change in the credit quality of the issuer or has identified a more attractive opportunity or when the sub-adviser seeks to manage the fund's duration or tax position or to provide liquidity to meet shareholder redemptions. The fund may use derivatives as a substitute for investing directly in an underlying asset, to increase returns, to manage duration, interest rate or foreign currency risk, or as part of a hedging strategy. The derivative instruments in which the fund may invest include typically futures (including those relating to securities, indices, foreign currencies and interest rates). The fund also may purchase or sell securities on a forward commitment, when-issued or delayed-delivery basis, which means delivery and payment take place at a future date at a predetermined price and/or yield. Show less