There’s a $60 billion reason why SoftBank Group Corp. founder Masayoshi Son might feel a little down.

His company has shed more market value in the past year than during any 12-month period over the past two decades, while his portfolio of private and public companies faces continued turmoil. And yet, Son remains unfailingly optimistic.

"I have no doubt at all. No matter what changes take place, I have never been doubtful,” Son told shareholders Friday of his belief in the information revolution that forms the underlying thesis for his investment strategy.