According to The New York Times:
Sprint and its corporate parent, the Japanese telecommunications giant SoftBank, have decided to drop their pursuit of T-Mobile US after conceding that antitrust regulators would block a deal in an industry that is dominated by just a few large players, a person briefed on the matter said on Tuesday.TV reports on this also noted that the SEC didn't look favorably on this merger, seeing it as likely to only hurt consumers rather than help them.
The decision, made at a Sprint board meeting on Tuesday afternoon, is the second failed effort by large American wireless carriers to merge in three years. And it represents a serious blow by SoftBank to develop a big new challenger to the two giants of the American cellphone industry, Verizon and AT&T.
[...] a proposed combination of Sprint and T-Mobile, uniting the third- and fourth-biggest carriers in the United States, had been fiercely questioned by officials at both the Federal Communications Commission and the Justice Department. In 2011, AT&T’s attempts to buy T-Mobile for $39 billion failed after the Obama administration sued to block the deal.
Still, SoftBank was forced to concede that such a union would have little chance of clearing either government regulator, this person said. One of the latest reminders that a merger would meet serious opposition came last week, when the F.C.C. signaled that it would prevent the two companies from making a joint bid in an upcoming government auction of wireless spectrum.
T-Mobile still isn't out of the woods yet, as it might have still other suitors, and its owner Deutsche Telekom still seems to want to sell it off.