Steamboat Ventures-backed Sometrics has sold 3.3 trillion units of its Game Coins virtual currency since launching in 2007, with more than 2 million users spending the currency every month.

Credit card provider American Express (Amex) has agreed to buy Sometrics, a US-based virtual currency company backed by media group Disney’s corporate venturing unit, for a reported $30m.

Sometrics has sold 3.3 trillion units of its Game Coins virtual currency (pictured) since launching in 2007, with more than 2 million users spending the currency every month, and news provider TechCrunch said Amex was paying $30m.

Disney’s Steamboat Ventures had led the $4m series B round for Sometrics in October…