Federal Reserve Policy: Interest rate changes and quantitative easing/tightening impact bond yields, influencing FIRXMX's net asset value. Higher rates generally decrease bond values.

Inflation Expectations: Rising inflation erodes bond values, as fixed income becomes less attractive. Inflation forecasts directly affect bond yields and the fund's price.

Credit Risk: Deterioration in the creditworthiness of bond issuers within the fund can lower its value, reflecting increased default risk.

Market Sentiment: General investor confidence or fear can drive bond prices up or down, affecting FIRXMX even if fundamentals remain unchanged.

Economic Growth: Strong economic growth often leads to higher interest rates, putting downward pressure on bond prices and the fund's NAV.

Supply and Demand: The supply of new bonds and investor demand for existing bonds directly impact bond prices within the fund's portfolio.