The Fidelity Sustainable Multi-Asset Fund Class M (FYMMX) is a mutual fund that focuses on investing in a diverse range of assets, including stocks, bonds, and other securities, with a focus on sustainability. This fund is managed by Fidelity Investments and aims to provide long-term growth while considering environmental, social, and governance factors. It is classified as a multi-asset fund, meaning it invests in a variety of asset classes to achieve its investment objectives. The "Class M" designation indicates that this fund is available for purchase through certain retirement plans.