The European Commission may not know it yet but another formal complaint about IBM and its mainframe monopoly is about to land with a resounding thud on its desk.

Neon Enterprise Software LLC, the Texas company with the IBM-outlawed widgetry to slash the notoriously crippling mainframe licensing fees that IBM charges, said Thursday that it's going to complain to the EC about IBM's "on-going anticompetitive and abusive conduct."

The company's already lodged a private antitrust suit against IBM in Texas but it won't come to trial until March of 2012. The suit also accuses IBM of disparaging Neon and its zPrime product and unlawfully interfering with and threatening customers purchasing zPrime.

Neon's will be the fourth complaint the EC has gotten in the last few years if you count the one made by mainframe-to-Itanium player Platform Solutions Inc (PSI) that IBM bought in 2008 to shut it up. There are also the complaints filed subsequently by t3 Technologies Inc and recently by TurboHercules SAS.

The Commission was pretty far down the investigative road before the PSI complaint was withdrawn and it's hardly likely to forget what it learned. It's thought it won't be able to ignore three complaints representing three wholly different kinds of products. Allen & Overy, the law firm drawing up Neon's complaint, is also a practiced hand at this sort of thing. It represented Sun when it made the very first complaint to the EC about Microsoft and look where that wound up.

The Justice Department is currently investigating IBM and its conduct in the mainframe market for antitrust and the EC has reportedly been conducting a parallel but still informal investigation.