Interest Rate Environment: Changes in prevailing interest rates, especially short-term rates set by the Federal Reserve, directly impact the yield, and therefore the price, of money market funds like FMWJXX.US. Higher rates generally lead to higher yields and potentially higher prices.

Credit Quality of Holdings: The creditworthiness of the securities held within the money market fund (Treasury bills, commercial paper, etc.) influences its perceived safety and thus its price. Downgrades in the credit ratings of major holdings can negatively affect the fund's price.

Supply and Demand: General market conditions and investor sentiment can affect demand for money market funds. Increased demand, driven by risk aversion or a search for yield, can push prices upward.

Fund Expenses: The expense ratio charged by the fund's manager affects the net return to investors. Higher expenses can lead to lower yields and potentially a less attractive price compared to similar funds.