T-Mobile buys most of U.S. Cellular in $4.4 billion deal

T-Mobile, the nation's second-biggest mobile carrier, plans to acquire most of U.S. Cellular in an acquisition worth $4.4 billion, the wireless carriers announced on Tuesday.

The deal involves cash and as much as $2 billion in debt, with Bellevue, Washington-based T-Mobile buying 30% of U.S. Cellular's spectrum assets as well as the regional carrier's customer accounts and retail stores.

U.S. Cellular customers will be allowed to keep their current plans or switch to a T-Mobile plan, the companies said. The transaction is expected to close in the middle of next year, pending regulatory approvals.