CMBS, or commercial mortgage-backed securities, are a type of fixed-income security backed by a pool of commercial mortgages. They are similar to residential mortgage-backed securities (RMBS), but they are backed by mortgages on commercial properties, such as office buildings, retail centers, and apartments.
CMBS can be an attractive investment for several reasons. First, they offer higher yields than many other fixed-income investments. Second, they are relatively safe, as they are backed by real estate. Third, they can provide diversification to a portfolio.