US regulators are preparing a formal anti-trust investigation into internet giant Google according to a Wall Street Journal report.
Journal sources 'familiar with the matter' alleged that the investigation aims to discover if the search giant abused the firm's market domination of web search advertising.
Previously Google came under the regular's eye following Google acquisitions but the new probe will be the first time that Google's core business, search advertising, will come under the microscope.
Mirroring accusations that have arisen in Europe, Journal sources said that the probe would look into whether Google unfairly increases the search engine ranking of the company's own services.
Google has around two-thirds of the market in the US and an even greater market share in Europe.