Google (GOOGL) is facing some intense antitrust scrutiny from U.S. regulators. The Federal Trade Commission, after meeting with the Justice Department, came to an agreement that it will investigate whether the tech giant used its Android platform to restrict competition. Officials are taking action after tech industry representatives reportedly complained about Google bundling its products and prioritizing its own services. The probe however, is still in its early stages. For Google, its Android system is an important source of online ad revenue. But, this isn't the first time the FTC is looking into the tech giant. Back in 2011, regulators opened an investigation related to its search function. According to market research firm International Data Corporation, Android currently leads the mobile phone market, holding 59.3% market share in the U.S. Apple's (AAPL) iPhone software comes in second, holding 38% market share. Microsoft's (MSFT) Windows and Blackberry (BBRY) phone platforms hold 2.35% and 0.36% of market share, respectively. TheStreet's U-Jin Lee reports from New York.