Google Plays Down Microsoft's Antitrust Complaint in Europe

BRUSSELS — Google played down the significance of an antitrust complaint filed by one of its main rivals, Microsoft, on Thursday and said its discussions were continuing with European Union regulators.

“We’re not surprised that Microsoft has done this, since one of their subsidiaries was one of the original complainants,” said Al Verney, a spokesman for Google in Brussels.

Google was “happy to explain to anyone how our business works,” Mr. Verney said.

Amelia Torres, a spokeswoman for E.U. Competition Commissioner Joaquin Almunia, said Google would be given “an opportunity to comment and to give its own version of the facts” following the complaint.

Ms. Torres emphasized that the E.U. investigation of Google was still at a “preliminary stage.”

Even so, the complaint significantly raises the stakes in Europe for Google, which is already the subject of a wide-ranging antitrust investigation opened by Mr. Almunia in November.

Google controls more than 90 percent of the market for Internet search in some parts of Europe and is well ahead of Bing, a rival search engine developed by Microsoft. Google’s search engine and its other sites have become hubs for advertisers and generate huge revenue for the company.

Until now many of the complaints in Europe against Google have focused on competition between search engines, and come from technology companies that are relative minnows in the sector. One of those complaints was made by a Microsoft subsidiary called Ciao, a price comparison site.

The new complaint by Microsoft increases the breadth of the European case by focusing on whether Google is denying a major rival access to key technologies like so-called application programming interfaces that facilitate access to Google’s products and services.

In particular, Microsoft claimed that anti-competitive practices by Google on the Web and in smartphone software were aimed at hindering rivals from examining and indexing information that Google controls, like its popular YouTube video clip service.

Microsoft also claimed that Google was stymieing advertisers and online agencies from using third-party software that could instantly compare results and move advertisers’ data from one ad platform to another — from Google’s Adwords to Microsoft’s Adcenter, for example.

Google has sought to portray itself as facing competition from social media like Facebook, which Internet users increasingly use as ways to link to other parts of the Web through recommendations from friends and other users.

Google has also said it does allow advertisers freedom to move data freely, and that the restraint on third-party software is to maintain the consistency of Google’s ad service.

Google could be fined as much as 10 percent of its annual worldwide revenue, which topped $29 billion last year, if found to have violated E.U. law. Google could also be required to adjust its business model as part of any remedy.

At their first face-to-face meeting in January, Mr. Almunia, the E.U. commissioner, assured Eric E. Schmidt, the chief executive of Google, he would give the company a chance to offer a way to settle the case without a fine or finding of wrongdoing, if any violations were found.