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Connecticut Avenue Securities

Connecticut Avenue Securities (CAS) is the benchmark for U.S. mortgage credit.

The Connecticut Avenue Securities® (CAS) program provides an opportunity to invest in a portion of the credit risk that Fannie Mae retains when we guarantee single-family mortgage-backed securities (MBS).

As of Q1 2022, $1.78T of unpaid principal balance of Single-Family mortgage loans is partially covered through CAS transactions, measured at the time of the transactions. 

Program Highlights

  • Since our first CAS issuance in 2013, Fannie Mae has developed the most liquid market for single-family mortgage credit risk.
  • As the largest manager of residential mortgage credit, we set the standard for managing credit risk throughout the life cycle of a mortgage – continuously innovating to reduce default risk and credit losses.
  • Underlying reference pools are large and highly diversified, offering broad exposure to the U.S. housing market.

CAS Investor Presentation   

Investor Resources

  • Institutional investors can invest side-by-side with Fannie Mae in our geographically diverse credit book of business. Access information on our broad investor base.
  • Data Dynamics®, our free analytics platform, allows investors to gain insights into historical loan performance trends, issuance profiles, and monthly performance.

CAS Transactions       CAS Ratings

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  • Contact us if you have questions or would like to learn more about the CAS program

In April 2018, SIFMA's TBA Guideline Steering Committee confirmed via a vote that it has not identified any issues that would impair the TBA eligibility of MBS under this new structure.

As a result, Fannie Mae released an updated Single-Family MBS Prospectus, effective for fixed-rate and adjustable-rate mortgage single-family pools with issue dates on or after May 1, 2018. These pools are issued under our Amended and Restated 2016 Single-Family Master Trust Agreement.