Taihei Kobayashi has gone from sleeping on the streets of Tokyo to heading a technology startup with a market value over ¥100 billion ($1 billion).

His rags-to-riches story is among the most remarkable to emerge from a small-cap stock boom that’s minting fortunes in Japan.

Kobayashi’s company, which helps startups and other firms design and create new businesses and products, went public in July. Since then, its shares have more than tripled.