Industry observers are scratching their heads after the Federal Housing Finance Agency this week took another step toward a future secondary mortgage market by announcing a plan to establish a single entity that would be used by Fannie Mae and Freddie Mac and at some point, perhaps, private issuers to issue mortgage-backed securities. Acting FHFA Director Ed DeMarco, in a speech before the National Association for Business Economics, laid out his plan for a single MBS platform that would be run by, and apparently developed by, an entirely new government entity separate from Fannie and Freddie. The platform, he promised, would have...