Sprint preparing to bid for T-Mobile: Report

Bridge Runner

Sprint is mulling a possible bid for T-Mobile-a deal that may leave the U.S. wireless market dominated by three mega-companies, The Wall Street Journal reported.

Sprint could launch a bid as early as the first half of next year, the report said citing people familiar with the matter.

The company is reportedly studying regulatory concerns before moving forward. Placing a bid despite regulators' concerns would be risky, and a bad reaction could put an end to the effort.

A deal between the third- and fourth-largest U.S. carriers could be worth more than $20 billion.

Sprint shares rose 10 percent in after-hours trading, while T-Mobile shares dipped 1.2 percent.

Sprint declined to comment to CNBC.

Click here to read the full report from The Wall Street Journal.

-CNBC's Ryan Ruggiero contributed to this article.

image: © Dino Kuznik