^A centuries-old Japanese tradition of stamping documents with seals in place of signatures is finally waning, as more people have been working from home due to the coronavirus pandemic. Corporate giants like Toyota and Nomura are signing up for the electronic signature services of a little-known company called Bengo4.com Inc., which has sent its stock soaring 100% this year.

The share-price surge made Bengo4’s founder, Taichiro Motoe, a billionaire largely based on his 67% stake in the Tokyo-listed company he founded 15 years ago. Forbes estimates Motoe’s net worth at just over $1 billion.

Investors are optimistic about Bengo4’s e-signature service, called CloudSign, in the Covid-19 era. As more people work remotely, Japanese companies are switching to e-signatures from physical stamps called hanko to authenticate documents—a practice Japan followed since at least the 1800s. “CloudSign is changing the traditional hanko