Federal Funds Rate: The primary driver, as FPVSXX invests in short-term US government securities. When the Fed raises rates, yields on these securities rise, increasing FPVSXX's yield and potentially its share price, and vice versa.

Economic Conditions: Strong economic growth can lead to higher interest rates as the Fed attempts to control inflation, boosting FPVSXX's yield. Conversely, economic slowdowns may cause the Fed to lower rates, decreasing FPVSXX's yield.

Inflation Expectations: Rising inflation expectations typically lead to higher interest rates to compensate investors for the eroding purchasing power of their money, thus impacting FPVSXX's yield positively.

Supply and Demand: Increased demand for FPVSXX, often seen as a safe haven during market volatility, can push its price slightly higher. Increased supply can lower price.

Government Debt Issuance: Increased Treasury bill issuance to finance government spending can influence supply and demand in the money market, potentially impacting yields and indirectly affecting FPVSXX.