Interest Rates: MMFJX.US, being a money market fund, is heavily influenced by prevailing interest rates. Higher rates generally lead to higher yields and potentially a slightly higher share price. Lower rates conversely compress yields and might lead to slight price depreciation.

Credit Quality: The creditworthiness of the securities held within MMFJX.US matters. If the perceived risk of default increases in these holdings, the fund's price might decrease. High-quality assets contribute to a stable price.

Fund Expenses: The expense ratio of MMFJX.US directly impacts the returns to investors. Higher expenses reduce the yield, potentially making it less attractive and indirectly influencing the share price relative to other funds.

Supply and Demand: While less volatile than stocks, fluctuations in investor demand for MMFJX.US can affect its price. High demand may lead to slight appreciation, while large redemptions might put downward pressure on the price.

Maturity of Holdings: The average maturity of the securities held within the fund influences its sensitivity to interest rate changes. Funds with longer maturities are typically more sensitive.

Economic Conditions: Overall economic health and outlook affect investor sentiment and interest rate expectations, thereby influencing the demand for and the performance of money market funds like MMFJX.US.