More than half of US state attorneys general are reportedly preparing an investigation into Alphabet Inc's Google for potential antitrust violations in a bipartisan effort led by Texas.

The investigation is set to be announced on September 9, and is expected to be presented by a smaller group of state attorneys general representing the broader effort, three people familiar with the matter told The Washington Post.

Antitrust action against Google poses a threat to its central business model, as the media giant could be forced to alter its practices and algorithms in ways deemed to be friendlier to competition and likely less profitable for Google, if the regulatory agencies or law enforcement officials find evidence of anti-competitive behaviour. Google could stand to face fines worth billions of dollars, as it already has from competition authorities in Europe, or even be forced to spin off business units like YouTube.

Mississippi Attorney General Jim Hood said in a statement: “I continue to be concerned with the aggregation of data in the hands of a few and am always watchful of any monopoly. As attorneys general, we need to evaluate and address specific conduct, utilizing our existing antitrust and consumer protection laws.”

“Google’s services help people every day, create more choice for consumers, and support thousands of jobs and small businesses across the country,” Google spokesperson Jose Castaneda said in a statement, adding that the company “continues to work constructively with regulators, including attorneys general, in answering questions about our business and the dynamic technology sector.”

The report came just two weeks after top Department of Justice antitrust official Makan Delrahim confirmed that “a couple of dozen state attorneys general have expressed an interest” in a joint investigation of tech companies such as Google, Amazon and Facebook. State attorneys general have already made clear their intention to get involved with Big Tech antitrust concerns. Attorneys general from 39 states along with the District of Columbia, Guam and Puerto Rico signed a letter to the FTC in June asking the agency to consider a broad range of factors in determining consumer harm.