Fannie Mae creates single-class MBS that represent beneficial ownership interests in a pool of mortgage loans secured by single-family (1-4 units) residential properties.

Creating a Single-Family MBS begins with a mortgage loan. The loan is made by a financial institution or other lender to a borrower to finance or refinance the purchase of a home or other property with 1 to 4 residential units. These loans are made to borrowers under varying terms (e.g., 15-year, 30-year, fixed-rate, adjustable-rate, etc.); during the life of the loan, the balance is generally amortized, or reduced, until it is paid off. The borrower usually repays the loan in monthly installments that typically include both principal and interest.

We pool single-family loans that generally conform to our standards and issue Single-Family MBS backed by those loans. A Single-Family MBS may be backed by fixed-rate mortgage loans or adjustable-rate mortgage loans but will not be backed by both fixed-rate and adjustable-rate loans.  When a Single-Family MBS is issued, we guarantee to the MBS trust that we will supplement amounts received by the trust as required to permit timely payment of principal and interest on the MBS certificates.

Single-Family MBS may be placed into Megas, REMICs, SMBS, or other Structured Transactions mortgage-related securities.

View Fannie Mae's Single-Family Disclosure Information Center to learn about the transition related to the Single Security initiatve.

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Additional data related to Single-Family MBS can be located via the tools on the right and via additional links outlined below.

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Fannie Mae guarantees to each MBS trust that it will supplement amounts received by the trust as required to permit timely payments of principal and interest on the certificates.

Page originally published: 12/21/11
Page last revised: 09/17/18

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