When Masayoshi Son was a boy growing up in Kyushu, he kept a notebook to scribble down inventions he hoped to create one day. Today, the SoftBank founder has almost $100 billion to invest in making the next big thing a reality.

Son's SoftBank Group Corp. closed the first round of a planned $100 billion investment fund, with money raised from Saudi Arabia, Abu Dhabi, as well as Apple Inc. and Qualcomm Inc.

The Vision Fund gives the 59-year-old access to a pool of capital unparalleled in the worlds of private equity or venture capital — the equivalent of four Silver Lakes or 15 Sequoia Capitals.