The Justice Department announced late Wednesday that Christine Varney, who heads the department's antitrust division, will be leaving her post early next month.
Varney's division is currently reviewing AT&T's proposed merger with T-Mobile USA. The $39 billion transaction would combine the nation's second biggest wireless provider AT&T with No. 4 T-Mobile and reduce the number of national mobile operators from four to three.
In a statement, the department said Varney will be leaving her post Aug. 5 - well before the agency is expected to finish its review of the AT&T-T-Mobile deal. The department did not say why Varney is leaving but several news reports said she plans to join the law firm of Cravath, Swaine & Moore.
"Christine Varney led the Antitrust Division with great distinction through a period when the department confronted a number of proposed mergers and other matters that could have led to higher prices, lower quality products and less innovation in a recovering economy," Attorney General Eric Holder said in a statement. "There is no doubt that her tireless work helped protect consumers and businesses from anticompetitive conduct and preserved competition in America's economy."
Justice, with Varney as head of the antitrust division, has been criticized for approving some controversial tech and telecom mergers including Comcast's merger with NBC Universal and Google's acquisition of travel software maker ITA Software.
Computer and Communications Industry Association President Ed Black praised Varney's efforts to "reinvigorate" antitrust enforcement but said he hopes the Obama administration will pick an antitrust division leader who will vigorously enforce the law to promote competition. Black's group has called on Justice to block the AT&T-T-Mobile deal.
"We hope the Obama administration will appoint a strong antitrust chief who understands the new economy and how competition spurs innovation and economic growth," Black said. "Sound antitrust enforcement is particularly critical to the tech industry."
Sprint also opposes the AT&T-T-Mobile deal. Sprint Senior Vice President for Government Affairs Vonya B. McCann praised Varney's service and said the firm is "confident that the DOJ's dedicated staff, as well as Varney's successor, will continue to carefully and expeditiously evaluate the dangers of the pending AT&T takeover of T-Mobile and determine that the creation of a duopoly, with control of approximately 80 percent of the wireless market, is a clear violation of our nation's antitrust laws."