A money market fund (also called a money market mutual fund) is an open-ended mutual fund that invests in short-term debt securities such as US Treasury bills and commercial paper. Money market funds are managed with the goal of maintaining a highly stable asset value through liquid investments, while paying income to investors in the form of dividends. Although they are not insured against loss, actual losses have been quite rare in practice. Regulated in the United States under the Investment Company Act of 1940, and in Europe under Regulation 2017/1131, money market funds are important providers of liquidity to financial intermediaries. Explanation Money market funds seek to limit exposure to losses due to credit, market, and liquidity risks. Money market funds in the United States are regulated by the Securities and Exchange Commission (SEC) under the Investment Company Act of 1940. Rule 2a-7 of the act restricts the quality, maturity and diversity of investments by money market funds. Under this act, a money fund mainly buys the highest rated debt, which matures in under 13 months. The portfolio must maintain a weighted average maturity (WAM) of 60 days or less and not invest more than 5% in any one issuer, except for government securities and repurchase agreements. Securities in which money markets may invest include commercial paper, repurchase agreements, short-term bonds and other money funds. Money market securities must be highly liquid and of the highest quality. History In 1971, Bruce R. Bent and Henry B. R. Brown established the first money market fund. It was named the Reserve Fund and was offered to investors who were interested in preserving their cash and earning a small rate of return. Several more funds were shortly set up and the market grew significantly over the next few years. Money market funds are credited with popularizing mutual funds in general, which until that time, were not widely utilized. Money market funds in the United States created a solution to the limitations of Regulation Q, which at the time prohibited demand deposit accounts from paying interest and capped the rate of interest on other types of bank accounts at 5.25%. Thus, money market funds were created as a substitute for bank accounts. In the 1990s, bank interest rates in Japan were near zero for an extended period of time. To search for higher yields from these low rates in bank deposits, investors used