As previously rumored, the FCC has officially approved SoftBank's purchase of Sprint and, furthermore, Sprint's purchase of the rest of Clearwire. Acting FCC Chairwoman Mignon Clyburn and commissioner Ajit Pai both gave statements supporting the deal, Sprint says that the FCC voted unanimously, though the third commissioner, Jessica Rosenworcel, did not issue a statement. In Clyburn's statement, she said that the deal would "serve the public interest" and that it would "accelerate the deployment of mobile broadband services and enhance competition."
The deal had seen multiple challenges from Dish, which has been trying to find a way into the wireless market and made aggressive offers for both Clearwire and Sprint at different points. Congress also expressed concern that SoftBank would use Chinese networking equipment in the US, making the company promise not to do so as part of the deal.
The FCC joins the Department of Justice and the Committee of Foreign Investment in approving the deal, and so there doesn't appear to be any more major roadblocks to the buyout. In its statement, Sprint says "This decision completes all Federal government reviews" and that it expects all of the deals to close in "early July 2013."
Update: AT&T, although it "took no position on the underlying transaction," has taken issue with the FCC's treatment of Clearwire's 2.5 GHz spectrum.