FlorianMueller writes: The European Commission announced today that it launched two parallel antitrust investigations into IBM's mainframe practices, following complaints lodged by T3 Technologies last year and French open source startup TurboHercules in March. EU regulators suspect an abuse of a dominant position and illegal tying of IBM's mainframe hardware to its proprietary mainframe operating system z/OS. There's even the possibility of a third case based on a complaint filed very recently by NEON, and the DoJ is also looking into this matter. IBM now finds itself in a situation previously experienced by Microsoft and Intel. This may also affect IBM's credibility when lobbying in the EU for open standards.