The Department of Justice and other allied parties this week reached a $1.375 billion settlement with Standard & Poor’s to resolve allegations that the firm’s investment-grade ratings misled investors into buying securities backed by badly underwritten mortgages. The agreement resolves the DOJ’s 2013 lawsuit against S&P and its parent, McGraw Hill Financial Inc., along with the suits filed by 19 states and the District of Columbia. Each of the lawsuits alleges that investors incurred substantial losses on residential MBS and collateralized debt obligations that carried S&P’s ‘AAA’ ratings, which effectively masked their true credit risks. S&P was accused...