The standardized short-term borrowing rate typically used in determining the interest rate of home equity lines of credit (HELOCs) or other commercial projects, as established by the Federal Reserve Board.

Many banks use the prime rate as the base rate, and then use the creditworthiness and collateral of the borrower to determine their mortgage rate (i.e. prime plus 1%, prime plus 2%, prime plus 3%, etc.)

• Also referred to as "prime"