Nintendo shares in Japan surged on hopes that the new Pokémon Go app would give the company's mobile gaming business a serious boost.



The stock closed up 24.52 percent on Monday at 20,260 yen ($199.70) per share; this followed Friday's gains of some 8.9 percent. Reuters reported that the company had added $7.5 billion to its market value in the past two sessions, while volume on Monday was at an October 2015 high.



David Gibson, an analyst with Macquarie Capital Securities in Japan, told CNBC's "Street Signs" that Friday's rally in Nintendo stock was all about the app's chart-topping performance in the U.S., while Monday's rally was "all about anticipating a very strong launch in Japan any day now."

The app was rolled out on July 6 and is currently available in the U.S., where it's dominating the list of top free apps on the App Store, as well as in Australia and New Zealand. It is expected to be released in Japan soon.



Pokémon Go uses augmented reality technology to allow users to catch virtual Pokémon characters in the gamers' real-life surroundings using their smartphone screens, as well as battle other Pokémon characters.



While the game appeared to have hit a mainly positive note among users, analysts had a more nuanced view of what this would mean for Nintendo's earnings.



Mia Nagasaka, an equity analyst with Morgan Stanley MUFG Securities, said in a note that for Pokémon Go to have a meaningful impact Nintendo's profits, the game needed to hit a minimum of 15 billion to 20 billion yen ($140 million to $196 million) turnover per month.



Currently, the game is freely available for download on the App Store and on Google Play but offers in-app purchases for additional items and power-ups.



Nagasaka added that the estimated daily turnover for Pokémon Go on the first day was around 400 million to 500 million yen ($3.9 million to $4.9 million), so in order to give Nintendo a serious leg up earnings-wise, the app needed to be consistently at the top position for sales on app stores.

Citing external data from SensorTower, Nagasaka explained the total monthly turnover from U.S. iOS and Android platforms for popular apps were near that turnover range. For example, she said, Game of War was the top app in June and brought in about 400 million to 500 million yen a day, with an estimated monthly turnover of 14 billion yen.

The number two app for June, Mobile Strike, had an estimated 10 billion yen monthly turnover, after bringing in about 300 million to 400 million yen daily.

"If [Pokémon Go] holds on to the top spot for sales, like other top-ranking titles, we would assume that monthly turnover reaches 10 billion yen or higher, but given particular characteristics of apps, at this point, we cannot comment with high certainty on [its] sustainability," she added.