SoftBank Corp. Chief Executive Officer Masayoshi Son Takes The Ice Bucket Challenge [Getty Images]

Billionaire Masayoshi Son, chairman and chief executive officer of SoftBank Corp., pours water over himself while taking part in the Ice Bucket Challenge to raise awareness for amyotrophic lateral sclerosis (ALS) in Tokyo, Japan, on Wednesday, Aug. 20, 2014. Son said after the event that he would "cool his head and think" when asked about the company's next step following an effort to acquire T-Mobile US Inc. through Sprint Corp. Photographer: Tomohiro Ohsumi/Bloomberg via Getty Images

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