Why Sprint is Certain to Launch a Price War

SoftBank cut retailer fees 35 percent to defend its small merchant point of sale service, operated with PayPal, from an attack by rival Square.

In October of 2003, SoftBank had launched a price war with Rakuten, Japan’s biggest Internet mall, by cutting fees for merchants to use SoftBank's online shopping portal. 

Those moves are consistent with SoftBank's approach to pricing for mobile service. SoftBank, it is fair to say, surprised the two larger Japanese mobile firms when it launched a price war upon acquiring Vodafone's Japan business, which had struggled to get market share.

Since 2006, SoftBank has maintained it always would offer lower prices than the other carriers.

So many believe Sprint will do so as well, once SoftBank has put all the necessary pieces into place in the U.S. market.

T-Mobile US already is attacking the market with lower prices, and seems to be taking market share primarily from AT&T.