Softbank profit doubles in 4Q despite mobile expansion costs

Despite the focus on its mobile operations, Son stressed in a briefing that Softbank is first and foremost an Internet company.

Its various holdings include stakes in Yahoo Japan Corp., My Space Japan K.K., Chinese e-commerce giant Alibaba, as well as a professional baseball team.

"It was not our aim for Softbank to be the No. 3 mobile company (in Japan)," Son said. "From the beginning, it was to become Asia's No. 1 Internet company and the world's No. 1 mobile Internet company."

Softbank reported earnings after the market closed. Before that, its shares fell 3.3 percent to 2,040 yen ($19.55) on the Tokyo Stock Exchange in a broad market decline.