Twenty insurers and reinsurers provided coverage on these two CIRT transactions. CIRT 2019-1 and 2019-2 together covered the largest combined pool of loans and provided us the most coverage that we have ever acquired through CIRT at one time. These two transactions also marked the first time that the CIRT structure has covered the modification costs related to loan workouts, similar to the coverage that has been provided through our Connecticut Avenue Securities. We are proud to be the leading manager of single-family residential credit risk in the industry, and to have taken a leading role in partnering with private sources of capital in transferring mortgage credit risk, building a market that barely existed even five years ago. As the CIRT program continues to grow, Fannie Mae remains committed to increasing liquidity in the risk-sharing market through the regularity and transparency of our credit risk transfer transactions, said Rob Schaefer, Vice President for Credit Enhancement Strategy & Management at Fannie Mae.
In CIRT 2019-1, which became effective February 1, 2019, Fannie Mae will retain risk for the first 60 basis points of loss on a $11.8 billion pool of single-family loans with loan-to-value ratios greater than 60 percent and less than or equal to 80 percent. If the $70.6 million retention layer is exhausted, reinsurers will cover the next 325 basis points of loss on the pool, up to a maximum coverage of approximately $382 million. With CIRT 2019-2, which also became effective February 1, 2019, Fannie Mae will retain risk for the first 60 basis points of loss on a $17.9 billion pool of single-family loans with loan-to-value ratios greater than 80 percent. If the $107 million retention layer is exhausted, reinsurers will cover the next 325 basis points of loss on the pool, up to a maximum coverage of approximately $582 million.
Coverage for these deals is provided based upon actual losses for a term of 10 years. Depending on the paydown of the insured pool and the principal amount of insured loans that become seriously delinquent, the aggregate coverage amount may be reduced at the one-year anniversary and each month thereafter. The coverage on each deal may be canceled by Fannie Mae at any time on or after the five-year anniversary of the effective date by paying a cancellation fee.
The covered loan pool for the CIRT 2019-1 and CIRT 2019-2 transactions consist of fixed-rate loans that were acquired by Fannie Mae from April 2018 through November 2018. A summary of key deal terms, including pricing, for these new and past CIRT transactions can be found at http//www.fanniemae.com/resources/file/credit-risk/pdf/cirt-deal-pricing-information.pdf.
Since 2013, Fannie Mae has transferred a portion of the credit risk on single-family mortgages with an unpaid principal balance of over $1.7 trillion, measured at the time of transaction, through its credit risk transfer efforts, including CIRT, Connecticut Avenue Securities (CAS), and other forms of risk transfer. As of December 31, 2018, $1.1 trillion in outstanding unpaid principal balance of loans in our single-family conventional guaranty book of business were included in a reference pool for a credit risk transfer transaction. Depending on market conditions, Fannie Mae expects to continue coming to market with CIRT and CAS deals that allow private capital to gain exposure to the U.S. housing market.