U.S. Markets close in 6 hrs

Sprint stock falls 10% on report T-Mobile merger is unlikely to be approved as currently structured

Christine Wang

The Justice Department is unlikely to approve a planned $26 billion merger between T-Mobile TMUS and Sprint S-GB , The Wall Street Journal reported Tuesday.

Staffers from the Justice Department have reportedly told both carriers that the deal may not be approved under its current structure, the Journal reported, citing people familiar with the matter.

Shares of Sprint plunged as much as 12% following the report.

A spokesman for Sprint declined to comment to CNBC.

About a year ago, T-Mobile and Sprint announced they had reached an all-stock stock deal to combine the companies . Shareholders of both companies approved the deal in October, which later received national security clearance.

But the deal's greatest regulatory hurdle was that it would combine the third- and fourth-largest wireless providers in the U.S., a market with only two other participants: AT&T and Verizon.

This is breaking news. Please check back for updates.

Read the full report in The Wall Street Journal.

More From CNBC