Bill Ackman Boosts Stake in Fannie Mae and Freddie Mac.

Activist investor Bill Ackman boosted his company's stake in both Fannie Mae and Freddie Mac on Monday. Ackman's company increased its previous investment from around 9.98 percent in Fannie Mae and 9.77 percent in Freddie Mac to more than eleven percent in each one. The billionaire hedge fund manager's Pershing Square Capital Management company is already the top holder in the two government-backed mortgage finance firms. The two agencies have returned to profitability.