Yield maintenance is a prepayment penalty on fixed-rate commercial mortgages — typically CMBS loans — calculated to compensate the lender for the interest income lost when a loan is repaid before maturity, preserving ('maintaining') the lender's yield as if the loan had run to term.
Yield maintenance is the dominant prepayment protection mechanism on CMBS (commercial mortgage-backed securities) loans and many life company commercial mortgages. Unlike a simple step-down prepayment premium (e.g., 5-4-3-2-1%), yield maintenance is formula-based and rises when interest rates fall — precisely when borrowers most want to refinance. Standard yield maintenance formula: Prepayment Premium = Loan balance × (Loan rate − Treasury yield for remaining term) × PV factor for remaining payments. The key inputs are (1) the loan's remaining scheduled payments, (2) the current yield on a Treasury security maturing closest to the loan's maturity date, and (3) a present-value discount. When Treasury yields are well below the loan rate, yield maintenance can be substantial — often 5-15% of remaining loan balance. Yield maintenance ensures that CMBS bondholders (who purchased bonds backed by the fixed-rate cash flows from the loan) are made whole when the underlying loan prepays. The borrower's prepayment premium is passed through to bondholders to replicate the interest they would have received. This is critical to CMBS market function and is governed by CMBS loan pooling and servicing agreements (PSAs). See the Securities and Exchange Commission's EDGAR database (sec.gov/cgi-bin/browse-edgar) for CMBS offering documents with yield maintenance formulas. Comparison: yield maintenance vs. defeasance — both protect the lender's yield, but defeasance replaces the loan collateral with Treasury securities rather than paying a cash premium. Defeasance is more complex to execute but often economically similar or slightly more favorable depending on the Treasury curve shape. See [[defeasance]].
A standard prepayment penalty is a fixed percentage of the loan balance (e.g., 3% in year 3) regardless of market rates. Yield maintenance is formula-based and inversely correlated with interest rates — when rates fall (and refinancing is most attractive), yield maintenance rises. This makes it a much more effective borrower lock-in mechanism for lenders. See CMBS offering documents on sec.gov/cgi-bin/browse-edgar for the exact formula in any specific loan.
CMBS loan terms are largely standardized by the PSA (pooling and servicing agreement) governing each securitization — individual borrowers typically cannot renegotiate yield maintenance terms post-closing. However, at origination, the choice between yield maintenance and defeasance (or a step-down penalty) is sometimes negotiable depending on the conduit lender's current portfolio composition. Consult a commercial mortgage broker before signing.
Most CMBS loans have a yield maintenance or lockout period covering years 1 through typically 2-3 years before the maturity date, followed by an open prepayment window in the final 90–180 days. The exact schedule is defined in the loan agreement. After the yield maintenance window closes, the loan may be freely prepaid or may allow defeasance instead. Review your loan documents for the specific open window and prepayment schedule.