MainePERS MM 0001 refers to the Maine Public Employees Retirement System's Money Market Fund. This is a fund offered by MainePERS that is designed to provide stable returns through short-term investments in high-quality, low-risk money market instruments. The MM 0001 fund aims to preserve capital and provide liquidity for participants while offering competitive yields. It is one of the investment options available to members of MainePERS to allocate their retirement savings.