Interest Rates: Changes in the Federal Reserve's interest rate policy directly impact GBAXX.US. Rising rates typically increase yields, potentially leading to higher prices.

Market Conditions: Overall economic stability and investor sentiment influence demand for money market funds like GBAXX.US. Flight-to-safety during uncertainty can drive up prices.

Credit Risk: While generally very low for GBAXX.US, the creditworthiness of the underlying securities in the fund's portfolio can affect its price. Downgrades could lead to a slight price decrease.

Fund Management: The skill of the fund managers in selecting securities and controlling expenses affects the fund's overall performance and indirectly its price.

Supply and Demand: Increased demand for GBAXX.US shares can lead to a slight price increase, and vice versa.

Expense Ratio: The fund's operating costs, expressed as an expense ratio, impact the net yield and therefore the attractiveness, which in turn may affect the price.