Interest Rates: Rising interest rates generally decrease FNMAX's value as newly issued bonds offer higher yields, making older, lower-yielding bonds less attractive.

Credit Risk: Increased concerns about the creditworthiness of mortgage-backed securities held by FNMAX can lower its price, reflecting potential losses.

Prepayment Risk: Faster-than-expected mortgage prepayments, often due to refinancing, can reduce FNMAX's yield and price, as principal is returned sooner than anticipated.

Economic Conditions: A weakening economy can increase mortgage defaults, impacting the value of the underlying mortgage-backed securities and FNMAX's price.

Inflation: Higher inflation can erode the real value of fixed-income investments like those held by FNMAX, potentially decreasing its price.

Market Sentiment: Overall investor risk appetite and demand for fixed-income assets can influence FNMAX's price, regardless of fundamentals.

Supply and Demand: Increased supply of similar funds or decreased demand for mortgage-backed securities can put downward pressure on FNMAX's price.