Square has raised $150 million in a funding round, led by the Government of Singapore Investment Corporation, that values the payments firm at $6 billion, according to the New York Times.
Existing investors Goldman Sachs and Rizvi Traverse Management participated in the round, according to the Times, citing a source. Square has confirmed the round but not its size or the investors.
The latest money comes as Square faces a fast changing payments landscape. In August Amazon stepped onto Jack Dorsey's territory with an aggressively-priced mPOS offering and since then Apple has made its long awaited entrance into the mobile money arena and eBay has revealed that it will spin PayPal off.
Even before the formidable new competition arrived, rumours were rife that Square's business is floundering. Despite revenues of $550 million, the firm posted a loss of around $100 million in 2013 and has burned through more than half of the $340 million it has raised since 2009 as it struggles with the thin margins on the 2.75% fees it charges merchants.
The company has sought to expand beyond its traditional arena of POS payments, launching a cash advance service for merchants and paying $90 million for San Francisco-based food delivery service Caviar.