Shares in US regional operator Leap Wireless gained 10 percent in trading yesterday on the back of reports that it has become a takeover target by AT&T.

According to sources at the Wall Street Journal, AT&T is “actively engaged in discussions” with a number of companies that hold licensed spectrum following the collapse of its US$39 billion merger with T-Mobile USA two months ago. As well as Leap, other targets are said to include Metro PCS and Dish Networks. But no deals are thought to be on the table yet and it would likely be months before talks come to fruition, people familiar with the matter said.

A tie-up with Leap could give AT&T access to spectrum in dozens of markets valued by J.P. Morgan Chase & Co. analysts at about US$2.1 billion, according to the report. Leap has a market cap of around US$686 million.

The two parties had positive talks last year when AT&T was looking to sell off some assets to try to gain regulatory approval for the T-Mobile transaction, say sources. 

According to Bloomberg, Leap’s shares rose to US$9.62 in New York trading yesterday, their largest percentage increase in more than two months. The San Diego-based operator is due to publish its fourth-quarter and full-year 2011 earnings today after the close of trading.