A prepayment penalty is a fee a lender charges when a borrower pays off a loan early. Lenders count on a set stream of interest, so paying off early cuts that yield short. The penalty compensates them and shapes how and when a borrower can refinance or sell.
Common structures include step down penalties, which fall over time such as 5% in year one down to 1% in year five, and yield maintenance, which makes the lender whole for lost interest. Defeasance, used on many CMBS loans, replaces the collateral with government securities that reproduce the payments.
Yield maintenance and defeasance can be expensive when rates have fallen since closing, sometimes reaching six or seven figures on large loans. Borrowers weigh these exit costs against the benefit of refinancing or selling before the penalty burns off.

