Deutsche Boerse's deal to buy NYSE Euronext has won conditional approval from the U.S. Justice Department, provided that a Deutsche Boerse subsidiary, the International Securities Exchange, divest its 31.5 percent interest in Direct Edge.  Direct Edge is the fourth- largest U.S. exchange, the department said.  Despite the divestiture, Deutsche Boerse and NYSE must continue to provide some services to Direct Edge, added. The $9 billion deal still faces serious antitrust headwinds in Europe where there have been weeks of negotiations during which European Union antitrust staff made clear their reservations about approving a combination of Deutsche Boerse's Eurex and NYSE Euronext's Liffe on concerns that the merged entity would have a monopoly over European listed derivatives trading. Both Boerse and NYSE Euronext have said they would not pursue the merger if they were asked to divest either Eurex or Liffe. A formal decision by the European Commission is not expected until January or early February.  [Reuters  12/22/11]