The Invesco High Yield Municipal Fund Class Y (ACTDX) is a mutual fund that focuses on investing in high-yield municipal bonds. These bonds are issued by state and local governments to fund various projects and are considered to have a lower risk of default compared to corporate bonds. This fund aims to provide investors with a steady stream of income through the interest payments from these bonds. As a Class Y fund, it is designed for institutional investors and has a lower expense ratio compared to other share classes. Overall, this fund offers a potential for higher returns while also providing tax-exempt income for investors.