Standard & Poor’s is evaluating comments on a proposal to incorporate new criteria for rating residential MBS backed by mortgage servicer-advance receivables. Issuance of servicer-advance MBS has been scarce in 2014 due to the heightened regulatory scrutiny on nonbank servicers and potential ratings volatility, leading to fewer purchases of mortgage servicing rights. So far, only one deal – a $400 million unrated servicer-advance securitization in early April – has been seen this year. But with additional clarity being provided in S&P’s proposed ratings criteria and the revised methodology getting finalized over the near term, “issuers may start feeling...