AB Intermediate Diversified Municipal Portfolio Advisor Class (AIDYX) is an open-end mutual fund managed by AllianceBernstein that seeks safety of principal and to maximize total return after taking account of federal taxes by investing at least 80% of its net assets in municipal securities, with at least 80% of total assets allocated to securities rated A or better; the portfolio emphasizes conservative, high-quality intermediate-duration municipal bonds, including tax-exempt obligations issued by states, U.S. territories, and political subdivisions such as counties, cities, and towns, supplemented by limited exposure to cash equivalents, U.S. Treasury bills, government securities, and corporate bonds. Primarily focused on the U.S. municipal bond market within the Muni National Short category, the fund maintains a portfolio with approximately 96% in U.S. bonds (predominantly municipal tax-exempt at 93%), 3% cash, and minimal non-U.S. bonds, targeting institutional and individual investors seeking tax-exempt income with limited interest-rate sensitivity and mid credit quality. Launched on June 26, 2015, the fund is domiciled in the United States, with total net assets of approximately $5.24 billion across share classes and an Advisor Class share size of $501.78 million as of recent data; it is managed by a team including Matthew Norton (since January 2016), Andrew Potter (since January 2018), and Daryl Clements (since September 2022), with a net expense ratio of 0.44% and daily pricing. AllianceBernstein, the fund's investment manager founded in 1967 through predecessor firms and headquartered in Nashville, Tennessee, operates globally with offices in major U.S. cities and internationally. Recent developments include a team transition in February 2023 with the departure of longtime portfolio manager Terry Hults, leading to an evolving management dynamic; additionally, AllianceBernstein enhanced its fixed income offerings in November 2025 by launching the AB New York Intermediate Municipal ETF and AB Core Bond ETF, conversions reflecting strategic expansion in active municipal and taxable fixed income strategies amid growth in its $83 billion municipal platform.