Sources close to the case told AFP that EU Competition Commissioner Margrethe Vestager will submit the proposal to a European Commission meeting, seeking approval to go ahead after three failed attempts to reach a settlement with Google dating back to 2010.
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European Commission spokesman Margaritas Schinas said Vestager would brief the press at midday. Vestager leaves later today for the United States where the European Union probe into Google has become politically sensitive as the 28-nation bloc negotiates a massive trade liberalisation accord with Washington.
US critics say the EU is being selective in targeting Google and significantly, the US Free Trade Commission dropped its own probe of the company, saying it had done enough to meet complaints.
If found at fault under EU anti-trust rules, a company faces a fine of up to 10 per cent of its annual sales - in Google's case, USD 66 billion in 2014.
EU Digital Commissioner Guenther Oettinger said at the weekend the EU needed "to bring or force Internet platforms and search engines to follow our rules in Europe," adding that the decision would be made "in coming days".
If approved, Vestager would announce a formal "statement of objections" against Google, laying out the EU's case against the company and seeking a response with a view to forcing changes in the way it conducts its business.
Google accounts for about 90 per cent of the EU search market. The Commission, which polices EU competition policy, launched an initial investigation into Google in 2010 following complaints from rivals such as Microsoft and Trip Advisor that it favoured its own companies when customers ran searches.
Vestager's predecessor, Joaquin Almunia, made three attempts to resolve the dispute but in each case intense pressure by national governments, rivals and privacy advocates scuppered the effort.
Google head Eric Schmidt met Vestager in March after she had called for a review of the investigation when she took office late last year.
The commissioner "wants to have a fair balance of views amongst the stakeholders and on that basis she will ensure she has all the facts up to date before engaging in any further steps," a spokesman said at the time.
In an apparent effort to meet some of the EU's concerns, Google announced a major reorganisation of its European operations in February which sources said was meant to simplify the business so it could respond better to customers and policymakers.