Supercell

SoftBank, a Japanese telecom company, is expanding its ownership in Supercell, which makes one of the world's most popular mobile video games.

SoftBank has increased its ownership share in Clash of Clans maker Supercell to 73.2 percent, SoftBank announced Monday. Full terms of the deal were not disclosed, but SoftBank said that it acquired all shares owned by external investors and that the remaining ownership is held by Supercell's management and employees. Current Supercell CEO Ilkka Paananen will continue in that role.

The investment comes two years after SoftBank acquired a 50.5 percent equity stake in Finland-based Supercell for $1.5 billion.

The increased investment illustrates the ongoing popularity of Clash of Clans. The game, which launched in 2012, is available on iOS and Android and puts gamers in a virtual world where they build an army, train troops, and attack one other to build their virtual empires. Millions of people play Clash of Clans each day and there are no signs of the game's popularity slowing down anytime soon.

In an interview with the Finland-based Kauppalehti newspaper in March, Paananen said his company generated 519 million euros ($569 million) in revenue in 2013 and 1.5 billion euros in 2014. Supercell's operating profit -- a measure of the difference between revenue and its earnings before interest, taxes, depreciation and amortization -- hit 515 million euros in 2014.

While some of Supercell's revenue and profit was derived from other games the company makes, including the strategy game Boom Beach and a farming title named Hay Day, the majority of its financial success comes from Clash of Clans.

It's that success that likely spurred SoftBank's increased investment. It's also that kind of success that has prompted companies to invest in mobile gaming. Last September, for example, Microsoft announced that it acquired Supercell competitor Mojang for $2.5 billion to get its hands on the wildly popular Minecraft franchise. Rovio, another Finland-based company, has built its Angry Birds franchise into an empire that includes a slew of games, theme park rides, plush toys, and next year, a full-length movie.

Even Nintendo, a company that has stubbornly stuck to traditional gaming on consoles and portable devices, has acknowledged the promise of mobile gaming, announcing earlier this year that it will bring some of its most popular franchises to smartphones.

The SoftBank-Supercell deal was completed Friday. In a statement, SoftBank said that its investment in Supercell makes the Clash of Clans creator the "core to its mobile content strategy."

SoftBank, which runs the Japanese carrier by the same name, has also owned an 80 percent share of US-based Sprint since 2013.

Neither SoftBank nor Supercell immediately responded to a request for comment.