European regulators are to push ahead with an investigation into IBM’s dominance of the mainframe market even though the world's largest IT company made the original complaint.

Last week IBM bought Platform Solutions Inc, (PSI) a low-cost mainframe maker.

PSI had been attempting to sue IBM and had protested to European anti-trust bodies about IBM's dominance of the market, but withdrew its complaint to Brussels just before the IBM deal was announced.

The European Commission has said it expected to continue its investigation into anti-trust issues related to IBM’s domination of the mainframe market, one official told the Financial Times.

PSI is a Silicon Valley-based manufacturer of lower-cost hardware capable of running IBM’s mainframe operational system. The company was founded by engineers from mainframe maker producer Amdahl.