Big name backing for mobile payments firm.
Reuters has reported that Branson has added to a pot that is already overflowing after a $100 million injection led by VC Kleiner Perkins Caufield & Byers in June. It also raised money from Visa in April.
So what are they all so excited about?
Well, Square is the firm that uses phones and tablets to bring credit card payments to huge numbers of retailers, sole traders, mobile workers and more.
The firm gives these businesses a dongle that has slots into a phone at one end and houses a credit card swiper on the other. When used with the accompanying software, it lets any merchant accept credit card payments without the need to buy in a specialist reader.
And it's working. The company recorded $10 million in daily transactions for the first time this past weekend, spokeswoman Katie Baynes told Reuters, up from the $4 million per day during the summer.
Square has said it is on track to process $2 billion worth of transactions this year.
Branson is the founder of the Virgin Group, but says this is a personal investment.