Hedge funds managed by Bill Ackman and Jeff Yass recently bought shares of Nike stock.Portfolio managers Bill Ackman and Jeff Yass share very little in common. Ackman is an activist investor who takes large positions in a small cohort of stocks. His fund, Pershing Square Capital Management, manages over $10 billion across just nine positions. In contrast, Yass helps manage Susquehanna International Group (SIG) -- a $57 billion fund with more than 5,500 positions.While taking a look through the most recent 1 ...