V Technology Co., a small Japanese supplier to display makers, added a surprising new shareholder last June: Renaissance Technologies.

For the secretive U.S. hedge fund started by Jim Simons, it turned out to be an especially savvy bet. Shares of V Tech, as it's known, surged almost threefold in 2016, with much of the gain coming after Renaissance first reported a stake. V Tech, whose market value has jumped to $690 million, posted the second-best stock performance in a broad index of Tokyo-listed companies last year.

While Renaissance is staying silent on why it built a $27.8 million position in the stock, V Tech President Shigeto Sugimoto says he's never been more confident about his company's outlook. He's betting V Tech will soon sign a revenue-doubling deal with one of the Chinese screen makers seeking to break Samsung Group's dominance of the latest big thing in mobile phones: organic light-emitting diode displays.