MTGDX is a mutual fund offered by Morgan Stanley that focuses on investing in mortgage-backed securities. These securities are debt instruments that are backed by a pool of mortgages, providing investors with a steady stream of income. The fund is classified as Class I, indicating that it is designed for institutional investors and may have lower fees and higher minimum investment requirements. With a ticker symbol of MTGDX, this mutual fund offers investors the opportunity to diversify their portfolio and potentially earn returns through the performance of the mortgage market.