The proposed merger between T-Mobile and MetroPCS still has plenty of regulatory hurdles to overcome, but now there's one less to worry about. Seemingly unconcerned with the plan, the US Department of Justice has allowed a 30-day waiting period (mandated by antitrust law) to lapse without objection. "Deutsche Telekom has reached an important staging post at the approval process of the merger of its subsidiary T-Mobile USA and MetroPCS," said T-Mobile's corporate parent in a statement.

For the fourth and fifth largest US carriers to combine, approval will also need to come from the Federal Communications Commission, the Committee on Foreign Investment, and of course investors. MetroPCS shareholders are slated to vote on the merger during an April 12th meeting. The company is imploring them to vote yes, warning "there is no assurance that MetroPCS will be able to deliver the same or better stockholder value" should the proposal fail. Executive boards at both carriers have already approved the merger, with T-Mobile aiming to migrate all MetroPCS customers over by 2015.