Strategy. Under normal market conditions, the Fund invests at least 80% of its net assets in municipal securities whose interest is free from federal income taxes, including the federal alternative minimum tax. Although the Fund tries to invest all of its assets in tax-free securities, it is possible that up to 20% of the Funds net assets may be invested in securities that pay interest that may be subject to the federal alternative minimum tax and in securities that pay interest subject to other federal or state income taxes. In addition, the Fund invests at least 80% of its net assets in municipal green bonds. Municipal green bonds are bonds that promote environmental sustainability. The proceeds of green bonds are typically … Show more… Under normal market conditions, the Fund invests at least 80% of its net assets in municipal securities whose interest is free from federal income taxes, including the federal alternative minimum tax. Although the Fund tries to invest all of its assets in tax-free securities, it is possible that up to 20% of the Funds net assets may be invested in securities that pay interest that may be subject to the federal alternative minimum tax and in securities that pay interest subject to other federal or state income taxes. In addition, the Fund invests at least 80% of its net assets in municipal green bonds. Municipal green bonds are bonds that promote environmental sustainability. The proceeds of green bonds are typically used for one or more of the following purposes: renewable energy, energy efficiency, pollution prevention and control, environmentally sustainable management of living natural resources and land use, terrestrial and aquatic biodiversity conservation, clean transportation, sustainable water and wastewater management, climate change adaptation, eco-efficient and/or circular economy adapted products, production technologies and processes or green buildings that meet regional, national or internationally recognized standards or certifications. A municipal bond issuer can choose to assign a green bond or similar label to its bonds in its offering documents: however, there is no regulation of green bonds as a class and no universal framework for issuing green bonds. In order to determine a green bonds authenticity, the investment manager completes due diligence on each bond to be purchased to determine whether it meets the green bond definition above. After reviewing offering documents and issuer websites, and, if necessary, conferring with the underwriter and issuer, the investment manager places prospective green bonds into one of the following three categories: Eligible for investment based exclusively on an internal evaluation of the bond. The investment manager determines that bond proceeds are being issued for environmentally-friendly projects or programs and that the issuer has adequate internal controls and disclosure practices. Eligible for investment based on an internal evaluation of the bond as well as an external evaluation by an independent party. The due diligence process is identical, but the investment manager also leverages an independent evaluation that some issuers engage to verify that the green bond label has been used appropriately to make its determination of authenticity. Not eligible for investment. The investment manager places bonds in this category if bond proceeds are not clearly used to promote environmental sustainability, project descriptions are inadequate, or disclosure practices and internal controls are weak. The investment manager screens all labeled green bonds and bonds with similar labels, but it also will consider bonds with no label for investment by the Fund. The due diligence process and categorization of non-labeled green bonds and labeled green bonds is identical. The Fund may invest in securities of any maturity or duration. In addition, the Fund may invest in municipal securities issued by U.S. Territories. The Fund does not necessarily focus its investments in a particular state or territory. The Fund buys predominately municipal securities rated, at the time of purchase, in one of the top four ratings categories by one or more U.S. nationally recognized rating services (or comparable unrated or short-term rated securities). The Fund may hold up to 20% of its net assets in municipal securities rated below investment grade (or comparable unrated or short-term rated securities). The Fund also may invest in insured municipal securities, municipal lease obligations, variable and floating rate securities (primarily variable rate demand notes), zero coupon securities and deferred interest securities. Although the investment manager searches for investments across a large number of municipal securities that finance different types of projects, from time to time, based on economic conditions, the Fund may have significant positions in municipal securities that finance similar types of projects. The investment manager selects securities that it believes will provide the best balance between risk and return within the Fund's range of allowable investments and typically invests with a long-term time horizon. This means it generally holds securities in the Fund's portfolio for income purposes, although the investment manager may sell a security at any time if it believes it could help the Fund meet its goal. With a focus on income, individual securities are considered for purchase or sale based on various factors and considerations, including credit profile, risk, structure, pricing, portfolio impact, duration management, restructuring, opportunistic trading and tax loss harvesting opportunities. Show less