Mobile payments company Square is valued at $3.25 billion

"Square, the mobile payments startup headed by Twitter co-founder Jack Dorsey, has closed a more than $200 million fundraising round that will value the company at $3.25 billion.
The company had previously raised $100 million in 2011 valuing it at more than $1 billion, and was first revealed to be seeking another round of funding in late July. According to Square’s press release announcing the news, the investors who participated in the latest funding round included Citi Ventures, Rizvi Traverse Management and Starbucks."

Source:  Mashable, 17th September 2012