Strategy. The Fund normally invests at least 80% of its total assets in investments the income from which is exempt from U.S. federal income tax (other than AMT). The Fund is an actively managed exchange-traded fund (ETF) that seeks to achieve its investment objective by investing, under normal circumstances, in investment grade municipal debt securities that fund issuers with operations or projects helping to promote progress towards sustainable development, in alignment with the goals and metrics defined by the United Nations Sustainable Development Goals (SDGs) 9, 11 and 12. The SDGs were adopted by the United Nations General Assembly to achieve sustainable development for all, and the specific goals of SDGs 9, 11 and 12 are as follows: SDG 9 is … Show more… The Fund normally invests at least 80% of its total assets in investments the income from which is exempt from U.S. federal income tax (other than AMT). The Fund is an actively managed exchange-traded fund (ETF) that seeks to achieve its investment objective by investing, under normal circumstances, in investment grade municipal debt securities that fund issuers with operations or projects helping to promote progress towards sustainable development, in alignment with the goals and metrics defined by the United Nations Sustainable Development Goals (SDGs) 9, 11 and 12. The SDGs were adopted by the United Nations General Assembly to achieve sustainable development for all, and the specific goals of SDGs 9, 11 and 12 are as follows: SDG 9 is to build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation, SDG 11 is to make cities and human settlements inclusive, safe, resilient and sustainable and SDG 12 is to ensure sustainable consumption and production patterns. The Fund normally invests at least 80% of its total assets in securities that support sustainable development. The Adviser determines which operations or projects of issuers it believes to be supportive of sustainable development and that promote beneficial environmental and social outcomes in U.S. communities and cities by utilizing the rules-based investment approach described below. The Fund's policy to normally invest at least 80% of its total assets in securities that support sustainable development is non-fundamental and may be changed without shareholder approval upon 60 days' prior written notice to shareholders. The Adviser primarily uses a rules-based investment approach which utilizes proprietary HIP (Human Impact + Profit) Ratings data for the application of impact criteria to security selection and portfolio management. HIP Ratings are produced and licensed from HIP Investor, Inc. (HIP or the Data Provider), which provides services to evaluate, rate and rank issuers and their securities based on data-driven, quantitative performance measures that demonstrate positive social, environmental and economic outcomes or mission accomplishment. The Advisers investment process begins by using HIP Ratings to screen municipal securities based on their SDGs 9, 11 and 12 ratings by HIP, Environmental, Social and Governance (ESG) ratings by HIP and Climate-Threat and Resilience ratings by HIP. HIP Ratings are only assigned to the municipal securities of issuers where at least one qualified opportunity zone is located in the issuers region. An opportunity zone is an economically-distressed community where new investments, under certain conditions, may be eligible for preferential tax treatment based on certification from the Internal Revenue Service. HIP, as the Data Provider, analyzes multiple data points of municipal securities to determine an estimate of the impact ( i.e. , net benefit to the community) each municipal security provides. The HIP Ratings used by the Adviser seek to evaluate the impact of municipal securities with respect to the goals and metrics defined by SDGs 9, 11 and 12, climate resilience, and overall net benefit to people, planet, and prosperity. These HIP Ratings are used by the Adviser to narrow the universe of eligible Fund investments to municipal securities that, based on the HIP Ratings, the Adviser believes have been issued to fund operations or projects that support or advance sustainable development, as well as promote positive social and environmental outcomes. Such municipal debt securities may include, but are not limited to, bonds issued in connection with (i) new or revitalized infrastructure ( i.e. , roads, bridges, tunnels, buildings, transportation of people and freight, affordable and safe housing and redevelopment of urban areas ( e.g. , green spaces), school or campus upgrades and Leadership in Energy and Environmental Design (LEED) qualified real estate); (ii) information and education systems ( i.e. , schools, research, financial services, communication services and technologies and information services); (iii) healthier communities ( i.e. , hospitals, food and nutrition infrastructure, waste systems, air quality and environmental management systems); (iv) cleaner energy ( i.e. , utilities, resource and material use); (v) inclusive and sustainable industrialization towards increased gross domestic product (GDP); (vi) action and resilience planning and projects to mitigate the effects of climate change and other natural disasters and hazards; and (vii) ensuring sustainable consumption and production patterns. The Adviser is not required to invest in any issuer rated by the Data Provider and the Data Provider is not acting as a sub-adviser to the Fund. Municipal securities that the Fund may invest in include securities issued by U.S. states and municipal governments, any of their political subdivisions, agencies, or instrumentalities, or by U.S. territories and possessions, such as Guam, the U.S. Virgin Islands, and Puerto Rico, and their political subdivisions and public corporations. The Fund may invest a significant portion of its assets in municipal obligations of issuers located in the States of California and New York. The Fund does not expect to invest in non-investment grade (or junk) securities. The Fund may invest in debt securities of any maturity or duration and does not have a target maturity or duration. Duration is a measure of a debt securitys price sensitivity to changes in interest rates. The longer the duration of a debt security, the more sensitive its market price is to changes in interest rates. The Fund seeks to reduce its exposure to credit risk by diversifying its assets among many municipal issuers and among the different types and maturities of municipal securities available. The Funds investment policy to invest at least 80% of its total assets in investments the income from which is exempt from U.S. federal income tax (other than AMT) may not be changed without shareholder approval. The Fund may count investments that generate income subject to the AMT toward its 80% investment policy. For purposes of this policy, the term assets means net assets plus the amount of any borrowings for investment purposes. This percentage limitation applies at the time of the investment. The Fund is classified as a non-diversified fund under the Investment Company Act of 1940 and, therefore, may invest a greater percentage of its assets in a particular issuer. As of April 30, 2024, each of the general obligation, special tax ( i.e. , revenue bonds backed by a special tax) and healthcare sectors represented a significant portion of the Fund. Show less