Shares in Nintendo, which owns 32% of the global phenomenon Pokémon Go, have tanked in trade on the Nikkei.
The stock closed down more than 17%, following a statement from the company late on Friday that the financial impact of the smartphone game would be “limited”.
Nintendo says the earnings from Pokémon Go were already factored in when it released its annual forecasts in April.
A week ago, Nintendo shares had almost doubled to $US42 billion since the game was released on July 6, first in Australia and then the rest of the world.
However, the shares started to slide on Wednesday as analysts questioned whether the earnings potential matched the market capitalisation.
They started to pick up again on Friday when Pokémon GO finally launched in Japan, the country of its birth, but started sliding again today when the Japan market opened.
Nintendo is due to post earnings for the first quarter on Wednesday. The company is forecasting full year profit of 35 billion yen ($A440 million), more than double last year’s 16.5 billion yen ($A210 million).