A mortgage-backed security (MBS) is an ABS where the specific assets behind the security are mortgages. A collateralised debt obligation (CDO) is an ABS where the specific assets behind the security are bonds, often a pool of MBS.

A CMO is a type of MBS, but CMOs are different because they are broken up into tranches, and the way the investors who own them get paid is different than with a traditional MBS.

Mortgage-backed securities (MBS) are investment products similar to bonds. Each MBS consists of a bundle of home loans and other real estate debt bought from the banks that issued them. Investors in mortgage-backed securities receive periodic payments similar to bond coupon payments.

CMBS are backed by commercial real estate properties such as office buildings, shopping centers, and hotels, while MBS are backed by residential properties. Commercial properties tend to have higher credit risks than residential properties due to their higher vacancy rates and lower occupancy levels.