Margrethe Vestager, the European Union's competition commissioner, will reportedly announce formal charges against Google tomorrow. The EU's top antitrust watchdog will go after the search giant for favoring its own services over rivals during web searches. Google tried to settle the case last year, but that fell apart after strong objections from European nations, telecoms, and media companies.

The European Union has long had a contentious relationship with Google. Its parliament approved a resolution last year calling for the breakup of the company's search and advertising business. Google is seen by many EU members as a far too powerful gatekeeper to the world's information, with a 90 percent market share of search activity in Europe. If it's found to have violated the EU's antitrust laws, the company could face penalties of over $6 billion.

Google has also been contending with the EU-mandated "right to be forgotten" since last year. It is clearly eager to avoid the kind of protracted battle that consumed Microsoft, which paid billions over the last decade after refusing to comply with an antitrust order from the European courts. The latest news, however, has inclined experts to think that EU regulators won't agree to settlement, but will pursue "fines and injunctions" instead.