RiverPark Advisors, LLC is a privately owned investment management and advisory firm founded in 2009. The firm is mainly owned by employees whose stake account for 84% of the firm. RiverPark Advisors, LLC, forwarded its SEC 13F Filings on November 4, 2014, for the quarter ended September 30, 2014. The Blackstone Group L.P. (NYSE:BX), Realogy…