Mobile payments startup Square has raised $100 million in Series C financing in a round led by high-profile venture capital firm Kleiner Perkins Caufield & Byers.
The funding puts Square's valuation at about $1 billion, according to widely reported estimates.
"To continue to empower everyone to accept payments anywhere, we've raised $100 million in our Series C Financing, led by @kpcb," the company announced today on Twitter.
Kleiner Perkins Caufield & Byers has backed several notable companies in the tech space, including Amazon.com, Google and Electronic Arts (EA). The venture capital firm also has a fund dedicated to iOS developers.
Square's latest round of venture capital financing marks a significant step up from its first two rounds. In late 2009, Square raised $10 million in its Series A round, followed by an additional $27.5 million in Series B funding in January 2011.
The company's latest influx of venture capital brings its total investments to $137.5 million.
Square, created by Twitter co-founder Jack Dorsey, allows small businesses to use smartphones to process credit card payments. The platform processes payments using a small, square-shaped credit card reader that plugs into the iPhone, iPad or Android-based devices.
In May, the company announced that 500,000 of its credit card readers have shipped since the company began offering them the previous year. The readers are provided free of charge to merchants, who pay a 2.75 percent fee for transactions processed by Square.