Watch out, AT&T and Verizon: Japanese telecom SoftBank could soon a close deal to buy T-Mobile, according to the Nikkei news service. SoftBank apparently hopes to acquire a majority of T-Mobile's shares via its own US subsidiary, Sprint, as soon as next spring. The estimated price tag? More than two trillion yen, or some $19 billion. Of course, there will be several legal hoops to jump through, including approval from the FCC and the Department of Justice. If the deal gets the green light, though, the top four mobile carriers in the US will shrink to three, with the combined might of Sprint and T-Mobile posing a bigger threat to heavyweights AT&T and Verizon Wireless. Stay tuned!