Initially, he was the only full-time employee at SoftBank, which, despite sounding like a tech start-up, operated “like an investment fund, with a portfolio of holdings<br />that Son would adjust based on changing growth rates,” Mr. Miki said.<br />The 59-year-old technology investor — a grandson of South Korean immigrants who has amassed one of Japan’s largest personal fortunes by pursuing grand,<br />Silicon Valley-inspired visions — is best known outside his homeland for buying the American mobile phone carrier Sprint for $21.6 billion in 2013.<br />“The goal was to become a 100 trillion-yen company,” Mr. Miki said, an amount equal to about $1 trillion.<br />SoftBank is buying ARM for a rich $32 billion, and it plans to plow another $25 billion in the Saudi joint venture over the next five years.<br />His goal is nothing less than to change how the material world works —<br />and to turn his company, the SoftBank Group, into the future’s most important technology business.<br />The investment displayed Mr. Son’s willingness to act on a general conviction: in this case,<br />that web portals would be crucial to the early commercial development of the internet.<br />And he is collaborating with Saudi Arabia’s ruling family to create what could become the world’s largest technology investment fund.<br />One item in the portfolio was Yahoo, an early investment that earned Mr.
