Richard Branson invests in Square

British entrepreneur Sir Richard Branson has invested an undisclosed sum in mobile payment start-up Square, founded by former Twitter chief Jack Dorsey, following a $110 million funding round.

Square, founded in 2010 and based in San Francisco, enables consumers and businesses to accept credit card payments on mobile devices.

Since its launch, Square has shipped more than 800,000 card readers to merchants and is currently processing more than $2 billion in payments annually.

Branson, founder of the Virgin Group empire, is the latest investor to pour funds into Square, although the figure is unknown.

The move comes after Square raised $100 million in a Series C financing round led by venture capital firm Kleiner Perkins Caufield & Byers.

According to Square, Branson took interest in the company’s “rapid growth and novel technology, in particular its free hardware that allows anyone to accept credit card payments”.

The company recently recorded $10 million in daily transactions, a spokesperson has revealed, up from the $4 million per day in gross payment volume that it announced earlier in the year.

According to the spokesperson, Branson’s involvement in Square is a “personal investment”. In a statement released by Virgin, Branson explained his interest in the company.

“I’m very passionate about helping people start and grow successful businesses, and Square is an incredible technology that inspires and empowers everyone to be an entrepreneur,” Branson said.

It’s been a busy year for Square, which has also signed deals with Apple, Best Buy, RadioShack, Target and Wal-Mart.

The company, which prides itself on facilitating credit card payments “anywhere, anytime”, says it plans to offer its mobile payments technology in international markets in 2012.

Square isn’t the only start-up Branson has invested in. Fellow US start-up Tumblr, a micro-blogging platform founded by David Karp, caught Branson’s eye earlier this year.

And according to Branson, there could be further investments on the horizon.

“I’m interested in a variety of sectors,” he told VentureBeat.

“In recent years, thanks in part to Virgin America, I’ve learned more about tech in general and social media in particular, and always look for companies that use business as a force for good.”