Fitch Ratings proposed a number of changes to its residential MBS loss model this week, as part of an annual review. The changes would prompt slightly lower loss expectations for most of the types of deals that are currently being issued. The rating service said the most meaningful proposed change with a positive implication on loss expectations is expected to be a lower default assumption for borrowers with strong equity positions. The lower default assumption was prompted by a proposed Cure Rate Adjustment. Fitch said...