Interest Rates: IVMXX.US is a money market fund, so its yield and price are heavily influenced by prevailing short-term interest rates set by the Federal Reserve. Higher rates generally lead to higher yields and potentially a higher price, while lower rates can decrease them. Credit Risk: Although money market funds aim for stability, the creditworthiness of the underlying securities (Treasury bills, commercial paper, etc.) still matters. Deteriorating credit conditions in the market could negatively impact the fund's perceived safety and potentially affect its price, though this impact is usually minimal. Supply and Demand: Market dynamics affect fund prices. High demand, perhaps due to investors seeking safe havens, can slightly push the price up. Conversely, large outflows could put downward pressure on the price. Fund Expenses: The fund's expense ratio, which covers management and operational costs, directly impacts its net yield. Higher expenses mean lower yields, potentially making the fund less attractive and impacting its price relative to competing funds.