The US company appealed the Commission’s decision to issue the record-breaking fine to the Court of First Instance of the European Court of Justice (CFI) in 2004.

The CFI hears all appeals against European Commission competition fines under Article 82 of the EC Treaty.

The Commission fined Microsoft €497,196,304 on March 24 2004, accusing the company of abusing its dominant position in two respects.

First, said the Commission, Microsoft had refused to supply "interoperability information" and allow its use for developing and distributing work group server operating system products.

Second, it said Microsoft had made the availability of its Windows Client PC Operating System conditional on customers acquiring Windows Media Player.

In its appeal, Microsoft claimed that it was not obliged to license its IP rights, and that the decision wrongly denied that Microsoft could rely on its IP rights as an objective justification for its alleged refusal to supply the technology.

It further claims that the Commission did not take account of the EU’s commitment under the TRIPs Agreement.

Microsoft also challenges the second allegation regarding Windows Media Player, which it says is based on a "speculative foreclosure theory", which is contrary to previous case law and to evidence that shows that content providers encode in multiple formats.

Microsoft also objects to the Commission’s requirement that it appoint and pay a trustee to monitor its compliance, saying that this is the responsibility of the Commission.

Finally, Microsoft says that there is no basis for imposing any fine in light of the "legal novelty of the finding of abuse" and that the amount of the fine is "plainly excessive".

The CFI consists of one judge from each EU member state, and normally hears cases arising from EU institutions in panels of three or five judges – although in important cases larger panels will sit.

The CFI can annul the Commission’s decision or uphold the decision but reduce the fine – which is more common in competition cases.

Either party can appeal the CFI’s decision to the European Court of Justice.

In July 2006, Microsoft was fined €280.5 million by the European Commission for allegedly failing to comply with the 2004 decision. Microsoft claimed it had complied and also appealed that decision.

Check Managing IP’s website, www.managingip.com, for details of the decision on Monday morning.

Managing IP and the Stockholm Network are organizing a seminar entitled "The day after tomorrow: the legal, economic and technological implications of the ruling on Microsoft v the European Commission" on October 3 in Brussels. Speakers include Meir Perez Pugatch of the Stockholm Network, Aurélien Condomines of law firm Aramis, Federico Etro of the University of Milan and Martin Campbell-Kelly of Warwick University. The seminar is free and you can register here.