This is why billionaires are piling into PayPal.Billionaire hedge fund pioneer Paul Tudor Jones of Tudor Investment reduced his stake in chip giant Nvidia in the first quarter, undoubtedly making a tidy profit on the sale. He then funneled that money into a new investment in embattled fintech company PayPal (PYPL 0.45%). Jones wasn't the only investor making this move, as Philippe Laffont of Coatue Management made a similar move, trimming his stake in Nvidia while adding to his PayPal position. The investor ...