Market Interest Rates: Rising interest rates typically decrease bond prices, as newly issued bonds offer higher yields, making existing ones less attractive. Conversely, falling interest rates tend to increase bond prices.

Credit Quality of Holdings: Deterioration in the creditworthiness of issuers within the fund's portfolio can negatively affect the fund's price, while improvements can have a positive impact.

Inflation Expectations: Higher inflation expectations often lead to higher interest rates, which can depress bond prices. Lower inflation expectations can have the opposite effect.

Economic Growth: Stronger economic growth may lead to higher interest rates and thus lower bond prices. Slower economic growth may lead to lower interest rates and higher bond prices.

Fund Management Strategy: The skill and strategy employed by the fund's managers in selecting and managing the bond portfolio can impact its performance and price.

Supply and Demand for the Fund: Increased demand for MMQSX.US relative to supply can push its price up, while increased supply relative to demand can push it down.

Maturity and Duration: Longer maturity bonds are generally more sensitive to interest rate changes. Duration measures this sensitivity. A higher duration fund will see bigger price swings.