Bruce Berkowitz, the money manager battling the U.S. government over the future of Fannie Mae and Freddie Mac, is calling on the boards of the mortgage-finance giants to build capital instead of turning over their profits to the Treasury Department now that they’ve returned to profitability.

The government-sponsored enterprises, which have been under federal conservatorship since they were seized amid soaring losses in 2008 “must now retain earnings to build a fortress-like balance sheet and keep promises made to millions of homeowners and savers,” Berkowitz wrote in letters to the boards of both companies dated Feb. 28.