The complaint from T3, a small US supplier of mainframes, said IBM has "a history of abusing its monopoly power in the mainframe industry", according to a statement from T3.
IBM is accused of engaging in a range of anti-competitive actions, including "preventing the sales of competing mainframe hardware products by tying the sale of its operating system to its mainframe hardware". IBM is further accused of "withholding patent licenses and certain intellectual property to the detriment of mainframe customers".
In its statement, T3 said it sold IBM mainframes but then moved into selling its own products, the Liberty line of mainframes, first developed by Amdahl Corporation, which itself is now part of Fujitsu.
In 2007, US software maker Platform Solutions filed a complaint with the Commission, alleging that IBM abused market dominance by refusing to supply interface information for mainframe computers or to license others to use its software. The action was dropped when IBM acquired Platform Solutions in July 2008.
That move sparked fears from the Computer & Communications Industry Association (CCIA) that it would lead to IBM dominating the mainframe market.
CCIA president Ed Black said at the time that the move "sucks the life out of the [mainframe] market leaving little prospects for anything but complete domination by IBM".
An IBM spokesperson told ZDNet UK on Tuesday: "As IBM has not seen any complaint, it is inappropriate to comment on specifics relating thereto." ZDNet UK has sought comment from T3, but had not received any at the time of writing.