Fund managers Bill Ackman of Pershing Square and David Tepper of Appaloosa Management saw their net worth increase significantly in the past year. Steve Cohen saw a $1.3 billion jump in his personal fortune. There were two newcomers to the list. Quant fund managers David Siegel and John Overdeck, cofounders of the $28 billion Two Sigma Investments, each has an estimated net worth of $2.8 billion. Two Sigma crushed it in 2014, with one of the funds ending the year up 57.55% and another one of the funds returning 25.56%, according to Forbes. On the flip side, numerous billionaire fund managers in...