Market Interest Rates: Rising interest rates generally decrease bond prices, as newer bonds offer higher yields, making older bonds less attractive.

Credit Risk: Changes in the perceived creditworthiness of the bond issuer (likely Fannie Mae in this case) affect bond prices; increased risk lowers the price.

Inflation Expectations: Higher inflation expectations erode the real value of future bond payments, leading to lower bond prices.

Economic Growth: Strong economic growth can lead to higher interest rates and potentially lower bond prices, while slower growth can have the opposite effect.

Supply and Demand: Increased supply of similar bonds can put downward pressure on the price of existing bonds, while increased demand can push prices higher.

Treasury Yields: Changes in the yields of US Treasury bonds, which are considered risk-free, often influence the yields and prices of mortgage-backed securities like FGNWTX.US.

Prepayment Risk: The risk that homeowners will refinance their mortgages when interest rates fall affects the cash flows of mortgage-backed securities and thus their prices.