A locked-in interest rate is a rate promised by a lender at the time of loan application. The promise is a legal commitment of the lender, though there may be qualifications or contingencies that allow the lender to charge a higher rate. On home loans, the lock-in is customarily provided for 1% of the amount borrowed, though often it is free of charge. However, many prospective lenders find ways to renege on commitments when interest rates rise.
