MBS industry observers had hoped that federal banking regulators would clear up any confusion about the treatment of collateralized mortgage obligations and real estate mortgage investment conduits when they finalized new liquidity coverage ratio rules last week. The regulators gave some hints, but did not spell out a position. The rubber will meet the road when examiners start going over individual banks’ portfolios for compliance with the LCR rule, which requires banks to maintain sufficient quantities of highly liquid assets to meet their cash needs in a financial emergency. The final rule classifies...