Urban Institute:

The GSE’s credit risk transfer (CRT) program is growing and tapping into a more diverse investor base, reducing the costs of CRTs and improving liquidity in this market. At the same time, the continued reliance on back-end transactions is cause for concern.
Freddie Mac‘s first two capital markets CRT transactions of 2017 have been different from previous Structured Agency Credit Risk (STACR) transactions in one important way. Unlike the pre- 2017 deals, in which the first loss piece (Tranche B) was 100 basis points thick, the first loss piece (Tranche B2) in the latest transactions is only 50 basis points thick while second loss piece (B1) is also 50 basis points thick. Splitting the old B tranche more granularly in this manner is a noteworthy development for a few reasons.