The head of Point72's Cubist unit, Ross Garon, is retiring and leaving the firm at mid-year, according to a memo from billionaire Steve Cohen sent this morning. Previously, Garon worked at D.E. Shaw, one of Cubist's main competitors, and founded his own hedge fund, Tykhe Capital, which was named after the Greek god of fortune. Garon joined Point72's predecessor, SAC Capital, in 2009. Visit Business Insider's homepage for more stories.