Standard & Poor’s maintained its grip on the subprime MBS rating business during the first nine months of the year, leading both in volume and in deals, a new analysis reveals. According to data compiled by Inside B&C Lending, S&P rated $288.56 billion in subprime MBS deals through the end of September, a total equal to 99.2 percent of the period’s $291.01 billion in total issuance. …