Hedge fund managers heavily populate the so-called 1 percent in the United States. And they are getting richer. The 25 highest-earning hedge fund managers in the United States took home a total of $21.15 billion in compensation in 2013, according to an annual ranking published on Tuesday by Institutional Investor’s Alpha magazine. They earned that hefty sum in a year when most hedge fund managers fell short of the market’s returns. The multibillion-dollar payday is the highest since 2010, and it is 50 percent more than in 2012, according to the survey.