Freddie Mac has launched its initial offering of bonds with exposure to actual losses on mortgages that it ensures. Structured Agency Credit Risk Debt Notes, Series 2015-DNA1 serve as reinsurance on $31.9 billion pool of mortgage loans backing MBS guaranteed by Freddie Mac. The notes are general obligations, but mortgage giant can hold on to interest or principal if loans in the reference pool default. All previous offerings STACR measured losses using a "fixed severity" approach. Essentially, investors take a hit once loans referenced in these deals are delinquent for more than 180 days. Loans six months behind on payments are assumed to be headed for default and a portion of the principal of these loans is repaid. The portion of the principal repaid is determined by the typical loss severity on loans in the reference pool. Last month Freddie announced plans to start offering exposure to actual losses, something it says that investors have asked for.