Japan's mobile carriers have come under government scrutiny for high phone bills that have helped bring years of enviable profit margins and given them a combined market value of more than $250 billion.
One of the most senior figures in government raised the possibility of a push to lower mobile bills in a speech on Tuesday. In unusually direct remarks, Chief Cabinet Secretary Yoshihide Suga said mobile carriers had room to lower bills by 40 percent.
The comments caused shares in the carriers to tumble, with two of the big three continuing to drop Wednesday after the trio lost a combined $9 billion in value the previous day.