After investors pushed up Nintendo Co. shares with a fervor only matched by gamers chasing Pikachu, traders are now locking horns over how much the high-flying stock is worth.

Bears have boosted short interest in Nintendo to its highest in five months after the stock doubled in just over a week. The other camp includes Yasuo Sakuma of Bayview Asset Management Co., who says the rally has long-term potential as the mobile app “Pokemon Go” is rolled out to more countries and the game-maker expands its location-mapping technology to the rest of its lineup, including “Super Mario Brothers” and “The Legend of Zelda.”

“The way the stock has risen is abnormal,” says Sakuma, Tokyo-based chief investment officer for the $2.6 billion fund manager. “For now, the stock needs to cool down, but there isn’t enough evidence to say that the ?4 trillion in market cap for the company is too high.”