The MainStay MacKay High Yield Municipal Bond Fund, Class I (MMHIX) is a mutual fund that primarily invests 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. The fund aims to provide investors with a steady stream of income through the interest payments from these bonds. As a Class I fund, it is typically only available to institutional investors and may have lower fees compared to other classes of the same fund. Overall, MMHIX offers a potential opportunity for investors to earn income while also diversifying their portfolio with municipal bonds.