The reports from sources such as the Nikkei, Japan's main business daily, and Kyodo News agency come as MetroPCS is in final negotiations to merge with Deutsche Telekom's T-Mobile USA. Those two firms announced they had agreed to merge earlier this month, but Softbank aims to convince MetroPCS shareholders that it can provide a better deal, the Nikkei said.
Softbank and Sprint have confirmed they are in talks, with Sprint saying they could lead to a "substantial investment." Softbank is looking to purchase at least two-thirds of its U.S. counterpart, according to reports.
Both operators are third in their respective countries, although Softbank could soon vault to number two in Japan, after a deal it announced earlier this month to acquire domestic rival eAccess for US$2 billion to help expand its mobile network.
The Japanese firm is mulling a total investment of over $30 billion in Sprint and MetroPCS, which would rank as the largest foreign acquisition of a foreign company, the Nikkei said.
A Softbank spokesman said the company had no comment on the reports of a MetroPCS deal.
The Internet conglomerate that owns Japan's third-largest as well as major online properties such as Yahoo Japan and large investments in foreign companies such as China's Alibaba Group, has aggressively expanded under the leadership of its CEO and founder Masayoshi Son.
Son has repeatedly made large gambles to expand his holdings in the past, including entering Japan's closed fixed-line Internet business, the acquisition of Vodafone's Japanese subsidiary, and betting big on Apple's first iPhone.
Combining Softbank and Sprint could make it cheaper for the new entity to purchase network equipment as well as phones and tablets for its network. Softbank's potential investments in the U.S. could also pass the scrutiny of domestic regulators, as it wouldn't reduce the number of operators in the country.