Founded in 2007, California-based Sometrics helps publishers make money from their online games through virtual currency with its in-game payment platform.
The company's system is used for 450 games with an audience of 225 million gamers in 200 countries, claiming to have distributed more than 3.3 trillion units of virtual currency credits.
Sometrics also runs GameCoins, a marketplace where gamers can exchange its currency for others, including Facebook Credits.
According to TechCrunch, Sometrics will be added to Amex's Serve platform, which enables users to buy goods and make person-to-person transfers online and through mobile phones.
American Express Buys Virtual Currency Monetization Platform Sometrics For $30M - TechCrunch