What happened

Shares of mobile communications companies T-Mobile (NASDAQ:TMUS) and Sprint (NYSE:S) jumped on Tuesday. As of 10:40 a.m. EST, T-Mobile stock was up 11% and shares or Sprint were up 72%.

The two stocks' big gains follow news that T-Mobile won approval from a federal judge to merge with Sprint. After the key win in court, the two companies are now moving to finalize their merger. 

A chart showing a stock price moving higher

Image source: Getty Images.

So what

U.S. District Court Judge Victor Marrero was unconvinced that a merger between T-Mobile and Sprint would give the two companies an unfair advantage or enable them to raise prices.

"T-Mobile has redefined itself over the past decade as a maverick that has spurred the two largest players in its industry to make numerous pro-consumer changes," Judge Marrero wrote in his ruling. "The proposed merger would allow the merged company to continue T-Mobile's undeniably successful business strategy for the foreseeable future."

"Judge Marrero's decision validates our view that this merger is in the best interests of the U.S. economy and American consumers," said Sprint's executive chairman, Marcelo Claure, in a joint press release with T-Mobile.

Now what

T-Mobile's $26 billion acquisition of Sprint could close as early as April 1, said T-Mobile's president and chief operating officer, Mike Sievert, in Tuesday's press release.

Among other benefits, the two companies expect that the merger will help them roll out a nationwide 5G network and ultimately offer better service and lower prices.