What are types of mortgage bonds?

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Mortgage bonds are a type of debt security that is backed by a pool of mortgages. These bonds are issued by government-sponsored enterprises (GSEs) such as Fannie Mae and Freddie Mac, as well as private financial institutions. The purpose of mortgage bonds is to provide a steady stream of income for investors, who receive regular interest payments based on the interest rates of the underlying mortgages. In this article, we will explore the different types of mortgage bonds and how they work.

Pass-Through Mortgage Bonds

Definition: Pass-through mortgage bonds are the most common type of mortgage bonds. These bonds represent an ownership interest in a pool of mortgage loans. The interest and principal payments made by the homeowners are passed through to the bondholders on a pro-rata basis.

Characteristics: Pass-through mortgage bonds have several key characteristics. Firstly, they have a fixed interest rate, which is determined by the weighted average interest rate of the underlying mortgages. Secondly, they have a stated maturity date, at which point the principal is repaid in full. Lastly, they are backed by the collateral of the underlying mortgages, providing a level of security for investors.

Collateralized Mortgage Obligations (CMOs)

Definition: Collateralized Mortgage Obligations (CMOs) are mortgage bonds that are structured into different classes, or tranches, based on the cash flows generated by the underlying mortgages. Each tranche has a different level of risk and return.

Characteristics: CMOs have several unique characteristics. Firstly, they have different maturities, with each tranche having its own stated maturity date. Secondly, they have different levels of credit risk, with the higher tranches having priority in receiving principal and interest payments. Lastly, they have different prepayment risks, as homeowners may choose to refinance their mortgages or pay them off early.

Credit Risk Transfer Securities

Definition: Credit Risk Transfer (CRT) securities are a type of mortgage bond that transfers the credit risk associated with the underlying mortgages from the issuer to the investors. These securities are issued by GSEs as a way to reduce their exposure to credit risk.

Characteristics: CRT securities have several notable characteristics. Firstly, they are designed to absorb credit losses on the underlying mortgages, providing protection to the issuer. Secondly, they may have different structures, such as senior/subordinated tranches or mezzanine tranches, depending on the level of risk transfer. Lastly, they may have variable interest rates or floating rate coupons, which can be tied to a benchmark interest rate.


In conclusion, mortgage bonds are an important financial instrument that allows investors to participate in the mortgage market. Pass-through mortgage bonds, collateralized mortgage obligations (CMOs), and credit risk transfer (CRT) securities are three types of mortgage bonds that offer different risk and return profiles. By understanding the characteristics of each type, investors can make informed decisions about their investment portfolios.


– Fannie Mae: www.fanniemae.com
– Freddie Mac: www.freddiemac.com
– Investopedia: www.investopedia.com/mortgage-bond