Shares in Nintendo jumped by 25 per cent in Tokyo on Monday thanks to the popularity of the company's new Pokemon Go smartphone game.
Since Thursday, the stock is up 36 per cent, adding about $7.5 billion US in market capitalization, Reuters reported.
The app, which has launched in the United States, Australia and New Zealand, quickly moved to the top of Apple's free app listings on iTunes. A launch in Japan and other countries is expected soon.
Based on characters from the Pokemon franchise, Pokemon Go is an "augmented reality" game which layers gameplay onto the physical world.
Whether the massive hit translates in money for Nintendo's bottom line remains to be seen. Nintendo only owns one-third of Pokemon Co., and the game was developed by Pokemon and Niantic, a Google spin-off, Reuters said.
"If nothing else, Pokemon GO has shown that there are 'dormant' Nintendo fans eager to trial its content for smartphones," analysts at Deutsche Bank wrote in a commentary.