The protection for a borrower against the danger that rates will rise between the time they apply for a loan and the time the loan closes. A rate protection can take the form of a "lock" or a "float-down". A rate "lock" is when the rate and points are frozen at their initial levels; however they can decline if the market rates decline. A rate "float-down" is when the rates and points cannot rise from their initial levels but they can decline if market rates decline.

Rate protection only runs for a specific amount of time, and if the loan is not closed within that period, the protection expires and the borrower will either have to accept the terms on the new loan quoted by the lender, or start the loan shopping process again.