SG Capital Partners is set to issue its first rated nonprime mortgage-backed security after bringing to market some unrated deals in recent years and aggregating loans in a rated nonprime MBS issued by a competitor. Morningstar Credit Ratings and S&P Global Ratings assigned preliminary AAA ratings to the planned $140.1 million SG Residential Mortgage Trust 2018-1 last week. Somewhat unusually, the rating services came up with different figures on the share of non-qualified mortgages ...