Nintendo shot past Sony in market value on Tuesday after shares in the video game giant more than doubled following the popular Pokémon Go game was launched.
The shares surged more than 14 percent to end at $300, up 120 percent from their July 6 close.
That put Nintendo's market capitalisation at $42.5 billion.
The rapid increase has made it more valuable than Sony, one of Japan's best-known companies, by about ¥400 billion (yen).
On Friday Nintendo, creator of the 20-year-old Pokémon franchise, set a record for the most shares ever traded daily in Japan.
— David Ingles (@DavidInglesTV) July 19, 2016
Since its launch two weeks ago, the game for mobile gadgets has sparked a worldwide frenzy among users who have taken to the streets with their smartphones.
The free app uses satellite locations, graphics and camera capabilities to overlay cartoon monsters on real-world settings, challenging players to capture and train the creatures for battles.
Investors are betting its popularity is a good sign for Nintendo's nascent push into mobile gaming, a major U-turn for a company that long insisted on a consoles-only policy.
The Pokémon craze has also boosted other shares in Tokyo.
One of them is McDonald's Japan.
It soared as much as 23 percent in the morning despite that it has been struggling to get past a series of food safety scandals
Because of the company on Friday giving away with some meals figurines based on the game's characters such as Pikachu.
After this new strategy it ended up 5.26 percent at ¥3,200 yen.
— Pokémon GO News (@PokemonGoNews) July 19, 2016
"Investors are flocking to Pokémon-related stocks and McDonald's Japan is one of those benefiting from the boom," said Mitsushige Akino, executive officer at Ichiyoshi Asset Management.
"The boom came at a time when McDonald's business has already started recovering and there's expectation that the Pokémon toy offering will further increase customer traffic to their shops."
A Vaporeon popped up in the middle of Central Park and this happenedpic.twitter.com/bSJ6GUvPvh
— Izzy Nobre (@MrNobre) July 16, 2016
The game was launched in the United States, Australia and New Zealand.
Since the weekend it has been released in more than two dozen more countries but has yet to be available in Japan.
Nintendo declined to say when the app would be released in its home market, and Niantic -- which developed the game for Nintendo -- did not reply to requests for comment.
Forbes cited Niantic chief executive John Hanke as saying the reason for the delay is that Japan's server capacity is not powerful enough to keep up with expected demand.