EU competition commissioner Margrethe Vestager is expected to formally file charges against US internet company Google on Wednesday (15 April), according to several media reports.

The commission has been investigating whether Google has abused its dominant market position in internet search to advance its other services since November 2010.

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Google has a market share of over 90 percent in many EU countries (Photo: Trey Ratcliff)

If Vestager does accuse Google of violating the EU's anti-trust rules, the company could theoretically face a fine of maximum 10 percent of the overall annual turnover of the company. In 2014, Google had $66 billion in revenue.

However, the highest fine the commission handed out to date was €1.06 billion, to US microchip company Intel, in 2009. The previous record was €899 million against Microsoft.

While the details of the charges are expected to be released at the commission's daily press conference at noon local time in Brussels, the main allegations in competition case 39740 have remained the same in the past four years.

Companies have accused Google of favouring its other services when consumers use Google Search.

Google's search product has such a dominant position in the EU – in some countries like Belgium its market share is as high as 98 percent – that under EU rules the company has “a special responsibility to ensure that its conduct does not distort competition".

Although Google and the previous competition commissioner, Joaquin Almunia, reached a settlement early 2014, the investigation was reopened later that year.

In her confirmation hearing before the European Parliament in October, Almunia's successor Vestager said new complaints against Google had emerged.

More recently, Vestager noted there is “no harm in being a big successful company”.

“The problem is how to be precise on what the complaints are. Can we substantiate that a very strong position is being used? That I can decide in a relatively short time span when I finalise the meetings, because I still have a few to go," she said in an interview with this website published in February.

Shortly after the expected announcement, Vestager will travel to the US where she meet antitrust officials in Washington DC and on Thursday she will hold a speech titled 'Competition policy in the EU: Outlook and recent developments in antitrust'.