Strategy. The Fund invests in a portfolio of municipal bonds, including municipal mortgage-backed and asset-backed securities. While current income is the Funds primary focus, it seeks to produce income in a manner consistent with the preservation of principal. Under normal circumstances, the Fund invests at least 80% of its Assets in municipal bonds, the income from which is exempt from federal income tax. This is a fundamental policy. For the purposes of this policy, Assets means net assets, plus the amount of borrowings for investment purposes. Up to 25% of the Funds Assets may be invested in municipal securities, the interest on which may be subject to the federal alternative minimum tax for individuals. The Fund also invests in municipal mortgage-backed … Show more… The Fund invests in a portfolio of municipal bonds, including municipal mortgage-backed and asset-backed securities. While current income is the Funds primary focus, it seeks to produce income in a manner consistent with the preservation of principal. Under normal circumstances, the Fund invests at least 80% of its Assets in municipal bonds, the income from which is exempt from federal income tax. This is a fundamental policy. For the purposes of this policy, Assets means net assets, plus the amount of borrowings for investment purposes. Up to 25% of the Funds Assets may be invested in municipal securities, the interest on which may be subject to the federal alternative minimum tax for individuals. The Fund also invests in municipal mortgage-backed and asset-backed securities, as well as restricted securities. The Fund may invest a significant portion or all of its assets in municipal mortgage-backed securities at the advisers discretion. The securities in which the Fund invests may have fixed rates of return or floating or variable rates. Municipal bonds are debt securities with maturities of 90 days or more at the time of issuance issued by states, territories and possessions of the United States, including the District of Columbia, and their respective authorities, political subdivisions, agencies and instrumentalities, the interest on which is exempt from federal income tax. The securities are issued to raise funds for various public and private purposes. Municipal bonds include private activity and industrial development bonds, tax anticipation notes and participations in pools of municipal securities. Sustainable in the Funds name refers to the Funds strategy to invest in sustainable securities. Under normal circumstances, the Fund invests at least 80% of its Assets in sustainable municipal securities as determined under the advisers investment process (the Sustainable 80% Policy). For purposes of the Sustainable 80% Policy, sustainable municipal securities are defined by the adviser as municipal bonds (as described above) whose use of proceeds, in the advisers opinion, provide positive social or environmental benefits. This policy may be changed by the Board of Trustees without shareholder approval. However, the Fund will provide shareholders with written notice at least 60 days prior to a change in its Sustainable 80% Policy. The adviser uses the use of proceeds process described below to identify investments for the Fund, other than its investments in derivatives, cash and cash equivalents. The adviser has determined that bonds that finance affordable housing, healthcare, municipal water and sewer, education, mass transit, and issuer designated green bonds promote positive social or environmental benefits for purposes of the Sustainable 80% Policy. In addition to the types of sustainable municipal securities noted above, the adviser may identify additional types of bonds and uses of bond proceeds that it believes will provide positive social or environmental benefits for purposes of the Sustainable 80% Policy. In order to identify and invest in other types securities that provide positive social or environmental benefits for purposes of the Sustainable 80% Policy, the adviser determines and assesses such securitys intended use of proceeds. Compliance with the Funds 80% Sustainable Policy is determined based on the securitys characteristics at the time of purchase. If the use of proceeds of a security changes after the time of purchase so as to no longer provide positive social and/or environmental benefits, the Fund may continue to hold the security. Up to 20% of the Funds Assets may be invested in cash and cash equivalents, derivatives, and investments that the adviser has not determined provide social or environmental benefits. The Fund may invest up to 20% of its total assets in securities rated below investment grade. Such securities are known as junk bonds, high yield bonds and non-investment grade bonds. Junk bonds also include unrated securities that the adviser believes to be of comparable quality to debt securities that are rated below investment grade. These securities generally are rated in the fifth or lower rating categories (for example, BB+ or lower by S&P and Ba1 or lower by Moodys). These securities generally offer a higher yield than investment grade securities, but involve a high degree of risk. A securitys quality is determined at the time of purchase and securities that are rated investment grade or the unrated equivalent may be downgraded or decline in credit quality, such that, following the time of purchase, they would be deemed to be below investment grade. If the quality of an investment grade security is downgraded subsequent to purchase to below investment grade, the Fund may continue to hold the security. As a matter of fundamental policy, the Fund will not invest more than 25% of its total assets: (i) in securities within a single industry; or (ii) in securities of governmental units or issuers in the same state, territory or possession. However, from time to time, the Fund will invest more than 25% of its total assets in municipal housing authority obligations. The Funds securities may be of any maturity, but under normal circumstances, the Funds duration will be the duration of the Funds Benchmark (Bloomberg US Municipal Index), as calculated by J.P. Morgan Investment Management Inc. (JPMIM), plus or minus two years. Duration is a measure of the price sensitivity of a debt security or a portfolio of debt securities to relative changes in interest rates. For instance, a duration of three means that a securitys or portfolios price would be expected to decrease by approximately 3% with a 1% increase in interest rates (assuming a parallel shift in yield curve). As of May 31, 2025, the duration of the Bloomberg US Municipal Index, as calculated by JPMIM, was 7.21 years, although the duration will likely vary in the future. The Fund may also invest in zero-coupon securities. Investment Process: The adviser buys and sells securities and investments for the Fund based on its view of individual securities and market sectors. Taking a long-term approach, the adviser looks for individual fixed income investments that it believes will perform well over market cycles. The adviser is value oriented and makes investment decisions after performing a risk/reward analysis that includes an evaluation of interest rate risk, credit risk, duration, liquidity, any security pledge, and a review of the securitys attributes such as the coupon, maturity and any redemption and tender provisions. The advisers risk/reward analysis along with its use of proceeds process allows the adviser to collectively evaluate those criteria when selecting securities for purchase. The adviser utilizes a proprietary framework to monitor the portfolios overall investment in bonds that have been designated as providing positive social or environmental benefits. Through the framework, the adviser assesses characteristics of bond issuances and their proceeds using third party data and/or internal research. The proprietary framework, as well as the advisers views on municipal bond use of proceeds, are periodically reviewed internally. Generally, the adviser determines whether or not to sell a security by looking at a number of factors such as the securitys attributes (e.g., coupon, maturity and redemption/tender provisions), liquidity, relative value and the credit quality of the security. The adviser also factors in the overall investment strategy of the Fund, including its positioning relative to the benchmark, its duration and its credit strategy, as well as the advisers interest rate outlook. Show less