The proposal could eliminate GSE eligibility as a standard for a loan to be deemed a qualified mortgage. The regulator aims to level the playing field between the non-agency market and Fannie/Freddie.

Eleven expanded-credit MBS have been introduced since June 15, with a total unpaid principal balance of $3.4 billion.

Three prime non-agency deals were brought to market at the end of June. One of them is backed by GSE-eligible investment-property loans.