Microsoft has filed another batch of technical information with the European Commission, in an effort to avoid an increase in fines resulting from a 2004 antitrust ruling against the company, a Commission spokeswoman said on Monday.

On 12 July the Commission fined Microsoft €280.5 million for not supplying the technical information about the communications protocols used by its workgroup server software requested in the antitrust ruling. The Commission calculated the fine at €1.5 million per day for the period from 16 December 2005, to 20 June, and warned the company that the daily fine could increase if it did not supply all the requested documentation by 31 July.

Since that warning, the company has supplied further documentation on the protocols, and the Commission is analysing it to determine whether it is complete, said the spokeswoman. "I don't know when the analysis will be finished," she said.

"From today, they could face a larger fine of up to €3 million a day" if the Commission finds the documentation lacking, said the spokeswoman.

In its March 2004 antitrust ruling, the Commission ruled that Microsoft had abused its monopoly in desktop PC operating systems to gain advantage in the markets for workgroup server operating systems and media player software. It ordered Microsoft to pay a €497 million fine, to offer a version of its desktop operating system Windows XP without a built-in media player, and to document the communications protocols used by Windows workgroup server products so that others could build competing products.

Numerous deadlines for the supply of the documentation have come and gone. The Commission initially gave Microsoft 120 days to provide the information, and threatened further fines in March and June last year. On 10 November the Commission told Microsoft that it would face fines of up to €2 million a day if it did not comply by 15 December, and finally imposed the €280.5 million fine on 12 July.

Microsoft representatives in Europe could not immediately be reached for comment.