Microsoft Corp has refused to comment on reports that the European Commission is reviewing complaints from competitors that it is using its dominance in the operating system market to build its position in the growing mobile software space.

According to a report in the Wall Street Journal, the EC officials have received complaints from a number of Microsoft's competitors about Microsoft's actions, and are reviewing the complaints. A spokesperson for Microsoft described the report as "speculative" and said that the company had no comment to make.

The report said that complaints from rival competitors focus on whether the next-generation of Microsoft's Exchange mail server software, codenamed Titanium, features application programming interfaces (APIs) that ensure that it works better with mobile devices based on Microsoft's own software than that of its competitors. Titanium's ability to link mobile devices to corporate applications is slated to be one of its most important new features.

Industry sources have confirmed to ComputerWire that there are concerns in the market that Microsoft is withholding Titanium interfaces from potential mobile software competitors, a move that would be contrary to Microsoft's settlement with the US Department of Justice and nine states, a provision of which was that Microsoft must expose certain Windows APIs and communications protocols to third parties.

The EC has not revealed the names of companies that have complained about Microsoft's actions. Long-term rival Sun Microsystems Inc has made complaints to the European Commission in the past, but refused to confirm or deny whether it is involved in the current complaints.

A complaint from Sun in 1998 that Microsoft designed its operating system to work better with its own server software than that of rivals prompted the EC's ongoing investigation into Microsoft's monopoly position. The Commission is also investigating whether Microsoft tied its Media Player software to the operating system.

Following the antitrust settlement between Microsoft and the US Department of Justice and nine states, the focus of attention has swung to Europe. A preliminary ruling by the European Commission on Microsoft is expected by the end of the year, with a final ruling coming next year. However, complaints regarding the mobile software space could see the investigation extended, however.

© ComputerWire