Fund Performance: The historical and recent performance of FSSZXX.US directly impacts its price. Higher returns typically attract more investors, increasing demand and thus the price.

Interest Rate Environment: Changes in prevailing interest rates, particularly those set by the Federal Reserve, strongly influence money market fund yields and therefore FSSZXX.US's price. Rising rates often lead to higher yields and potentially higher prices.

Credit Quality of Holdings: The creditworthiness of the securities held within FSSZXX.US, such as Treasury bills and commercial paper, affects its perceived safety and attractiveness. Downgrades in credit ratings of these holdings can negatively impact the price.

Fund Management Fees: The fees charged by the fund's management team impact the net return to investors. Higher fees may reduce attractiveness and potentially lower demand, thus impacting the price.

Investor Demand: Overall investor sentiment and demand for money market funds, influenced by factors like risk aversion and economic outlook, significantly affect the flow of capital into and out of FSSZXX.US, which in turn affects its price.