Fixel led the $13-billion unit through deals that made billions of dollars in profit for the New York-based firm. : Lee Fixel, head of Tiger Global Management’s private equity business, is leaving the firm after more than a decade to manage his own money. Fixel, who’s a partner at the $26 billion firm, will depart on June 30, Tiger Global said in an email to investors seen by Bloomberg. Scott Shleifer will take over as head of the unit. Fixel, 39, may start his own investment firm, according to the email.