Europe's antitrust chief has been accused of anti-US bias over the launching of monopoly and tax cases against Google and Apple.
"Some claim that our cases involving internet giants such as Apple or Google are evidence of bias. Well, that is a fallacy," she said in the text of a speech that will be delivered at the Foreign Policy Association in New York.
"Yes, US companies are often involved when we investigate the digital industry. But you will also see many Japanese firms in our car-part cartel cases."
Vestager was adamant that no fines made against such cartels and mergers had a geographical bias, despite other cases against major US companies such as Amazon and Starbucks in the past year.
Criticism was originally levied at Vestager by the US media, claiming that her pursuit of American companies is a way for European Commission (EC) regulators to protect companies in the Eurozone from overseas competitors.
Much of this stemmed from the EC's antitrust case against Google over allegations that the firm favours its own shopping service over those of others when consumers use its search engine.
"In the case of Google I am concerned that the company has given an unfair advantage to its own comparison shopping service, in breach of EU antitrust rules," Vestager said when the investigation began.
Unsurprisingly, Google denied claims that it has a near monopoly in Europe and will make a case to disprove the allegations.
"We respectfully but strongly disagree with the need to issue a Statement of Objections and look forward to making our case over the weeks ahead," said Amit Singhal, senior vice president of Google Search.
The environment for more criticism was further charged with the EC's probe into Google over anti-competitive behaviour with its Android mobile software.
The EU also garnered more attention from the US press when its antitrust authorities accused Apple of having tax arrangements designed to give the company a financial boost in return for providing jobs in Ireland.
Apple denied any truth behind such accusations, and said that it does not use tax gimmicks.
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