Money market funds, a special kind of mutual funds regulated by Rule 2a-7 of SEC Investment Company Act of 1940, are one of the investments with lowest risk which has been deemed and used almost equivalently as savings accounts with a bit higher return. However, money market funds are not insured by FDIC as are savings accounts. Last September, two money market funds went below $1.00 net asset value, which is also known as "broke the buck." This resulted in many law suits filed against the failed fund companies on misleading information once investors, especially many municipalities who invested tax payers' money in them, realized that they could not get back 100% of their money. I reviewed related SEC regulations and investigated into money market funds' information about their risks. After the cases of failed funds, most money funds now have clear indications on that they are different from savings accounts and are not FDIC insured. Additionally, I investigated the portfolio holdings and other financial facts of popular money market funds and collected data from both before and after September to obtain comparisons. Many funds have significantly lowered their risk level by cutting the percentage of risky investments, such as commercial paper, in their portfolio. Furthermore, most of the popular funds that are highly rated now are the huge ones with relatively low risks and low expense ratio, as opposed to the ones with high risks and high expense, since investors are very risk averse nowadays.