Japanese conglomerate SoftBank and German carrier Deutsche Telekom are close to a deal that would merge T-Mobile US with Sprint, eliminating one of the four major mobile competitors in the U.S., according to the Nikkei news agency.

SoftBank would pay more than 2 trillion yen (US$19 billion) for a stake of up to 70 percent in T-Mobile, which is the fourth-largest mobile operator in the U.S., Nikkei said, citing unnamed sources. SoftBank already owns a majority of Sprint, the country’s third-largest carrier. T-Mobile is majority owned by Deutsche Telekom.

The Wall Street Journal had reported earlier this month that Sprint was studying regulatory concerns about such a deal and might make an offer for T-Mobile in the first half of next year. The Nikkei story, posted on Wednesday in Japan, said the parent companies of Sprint and T-Mobile were in the final stages of talks on a possible deal. SoftBank might make its offer as early as spring 2014, Nikkei said, roughly matching the earlier report on timing.

A $19 billion price tag for T-Mobile would nearly equal the $21.6 billion that SoftBank paid for 78 percent of Sprint earlier this year.

Combining Sprint and T-Mobile would create a carrier with nearly 100 million customers, close to subscriber parity with AT&T and Verizon Wireless, each of which has more than 100 million. However, U.S. regulators might block such a transaction in order to preserve competition in the nation’s wireless industry. When the government shot down AT&T’s proposed takeover of T-Mobile in 2011, some regulators cited the need to keep four major rivals in the market.

T-Mobile has proved a scrappy competitor since emerging from the failed AT&T deal. In the past year, in a successful bid to make gains against its bigger rivals, the company has introduced new service and device-purchase plans that other U.S. carriers have emulated.