By Supantha Mukherjee

STOCKHOLM (Reuters) -Swedish fintech Klarna on Wednesday said it would launch an unlimited mobile plan in the U.S., joining other finance companies moving into the telecoms business, including British rival Revolut.

A number of fintechs, including Germany's N26 and Brazil's Nubank, have started offering mobile services in various countries as they seek to diversify their revenues.

Other investors outside the fintech arena have also put money into the mobile services business such as actor Ryan Reynolds and on Monday U.S. President Donald Trump's family business also licensed its name to launch a mobile service.

Klarna's mobile plan, which includes unlimited 5G calls and data for $40 per month, will use the platform provided by U.S. mobile services startup Gigs.

Google-backed Gigs, which as a partnership with AT&T, makes it easier for any company to become a mobile virtual network operator (MVNO) and sell mobile services to customers without owning the infrastructure that provides them.

Klarna, which paused its plans for an initial public offering in April, has more than 25 million users in the U.S. and the fintech is increasingly choosing the country to launch new products.

"Our ambition has always been to solve everyday problems ... mobile is a natural next step in building out our neobank offering," Klarna CEO Sebastian Siemiatkowski told Reuters.

Most global fintechs have started a mobile service in other countries before entering the U.S., but Klarna plans to start in the U.S., its largest market, and roll out in the UK, Germany and other markets later this year.

"There will be significant disruption to the MVNO market over the next two years, as enterprises try their hand at launching their own MVNO service," Juniper Research analyst Alex Webb said.

"However, increased competition brings increased risk, so not all MVNO projects are likely to be successful."

U.S. MVNO market size is estimated at $14.83 billion in 2025, and is expected to reach $20.84 billion by 2030, according to research firm Mordor Intelligence.