The European Commission last year charged Google with favouring its own advertising services, opening its fourth case against the world's most popular search engine.

In an effort to quell monopoly concerns in the EU, Google reportedly offered to sell its AdX advertising marketplace. Sources told Reuters that European publishers rejected Google's offer, arguing that the company would have to divest more in order to dismantle the conflicts of interest in its online advertising operations.

Following a complaint from the European Publishers Council, the European Commission opened its investigation of the search giant, charging Google with violating its antitrust laws by using its advertising technology to undermine and unlawfully block rivals.

Google won a court fight with the European Union over a €1.5 billion ($1.7 billion) fine for thwarting competition for online ads, partly making up for last week’s crushing defeat in a separate judgment for abusing its monopoly powers.

Google has avoided a European Union $1.7 billion antitrust penalty over its AdSense advertising platform thanks to a Wednesday ruling from the EU General Court. The court annulled the European Commission fine.