Interest Rates: Rising interest rates generally decrease bond prices, as newly issued bonds offer higher yields, making existing bonds less attractive.

Inflation: Higher inflation erodes the real value of future bond payments, leading to lower bond prices to compensate investors.

Economic Growth: Strong economic growth can lead to expectations of higher inflation and interest rates, thus potentially reducing bond prices.

Federal Reserve Policy: Actions by the Federal Reserve, like raising or lowering the federal funds rate or quantitative tightening, significantly impact bond yields and prices.

Credit Risk: Although US government bonds are considered low risk, changes in the perceived creditworthiness of the US government can still affect prices.

Supply and Demand: Increased supply of new 5-year Treasury bonds can lower prices, while higher demand can increase them.