Bill Ackman, the founder of Pershing Square Capital Management, is highlighting the opportunity to scoop up shares of the Federal National Mortgage Association, the government-backed home loan giant better known as Fannie Mae, and its rival Freddie Mac on the cheap before the US government unwinds its massive stakes in the companies. After a late December social media post laying out his case for the trade, the stocks skyrocketed 45% in less than an hour, and have continued to climb, but experts
