A federal judge last week granted limited discovery to a hedge fund representing a group of Fannie Mae and Freddie Mac shareholders as they challenge the government’s “net worth sweep” of their profits. But the court will keep a tight lid on public access to the documents in a nod to the government’s claim that a leak could have dire economic consequences on the mortgage market. Fairholme Capital Management has been pushing hard for discovery and access to internal government documents since the shareholder filed suit last summer demanding that the Treasury Department void its August 2012 Third Amendment to its preferred stock purchase agreement with Fannie and Freddie. In her ruling, Judge Margaret Sweeney of the U.S. Court of Federal Claims was...