PennyMac Mortgage Investment Trust (PMT) is finally coming to market with its much-awaited private residential mortgage backed securitization vehicle.

The mortgage pool backing PMT 2013-J1 is comprised of 691 first-lien mortgage loans with an aggregate principal balance of $550.4 billion, said Kroll Bond Ratings in its presale report.

The loans in the pool are all 30-year fully amortizing fixed-rate mortgages, Kroll states. There are no interest-only loans in the pool.

The pool is characterized by substantial borrower equity in each mortgaged property, as evidenced by an average loan-to-value ratio of 70% and a combined LTV of 71%.

The average credit score of the mortgage pool is 770.

Kroll anticipates investment-grade paper, primarily triple-A.