T3 Technologies (T3) has made a complaint to the European Commission alleging that International Business Machines (IBM) has abused a dominant position in the market for computer mainframes. T3's Complaint, of 20 January 2009, alleges that IBM's practice of selling its operating system alongside its hardware mainframe is a form of "tied sale" which is designed to restrict sales of competing mainframe hardware products. Further, it is alleged that IBM has withheld patent licenses and intellectual property in a manner that is disadvantageous to mainframe customers.