The first rated post-crisis non-agency MBS backed by a significant share of nonperforming mortgages paid off recently, offering insights into how the deal performed and how investors fared. The $372.80 million Mortgage Fund IVc Trust 2015-RN1 was issued by Bayview Asset Management in October 2015. It received “A” ratings from Fitch Ratings and Morningstar. Fitch said it capped its rating “due to the idiosyncratic and adverse-selection risks associated with NPL collateral.” At issuance, 34.9 percent of the loans were nonperforming and 78.0 percent had been modified. The rating services said...