Yuzo Kano quit Goldman Sachs Group Inc. twice: once for a rival bank, the second time to open Japan's first bitcoin exchange since the collapse of Mt. Gox.

When Kano, 38, left his job as a derivatives and convertible bonds trader in December, the bitcoin had climbed to a record $1,151. Three months later, each was worth half that after a $530 million heist at Tokyo-based Mt. Gox bankrupted what was once the virtual currency's largest exchange.

"That's one less competitor for us, but it also left many Japanese with a very negative impression of bitcoins," Kano said in an interview in Tokyo on July 17. "We already had a company then and felt it was up to us to rebuild the trust."