Lehman Brothers Commercial Mortgage-Backed Securities Index investment & finance definition

A performance benchmark for commercial mortgage-backed securities. All of the bonds in the index must be private transactions and cannot be agency deals. The collateral for each transaction must be new issues. The minimum transaction size must be at least $500 million to be included and $300 million to remain in the index.

The CMBS Index has four subsectors:

1. The CMBS Investment Grade Index measures return for investment-grade classes.
2. The CMBS High-Yield Index measures return for non-investment grade and nonrated classes.
3. The CMBS Interest-Only Index measures return for interest-only classes.
4. The Commercial Conduit Whole Loan Index measures return for all bond classes and interest-only classes.