A group of US state attorneys general have opened a probe into Google, the top law enforcement officer for Texas, Ken Paxton said today.
The antitrust investigation is led by Paxton and will look into big technology firms, with a focus on Google’s advertising arm.
Only two states attorneys general, those from Alabama and California, have not signed up to the joint effort.
It comes amid growing pressure on technology giants from authorities in the US. Last Friday a separate group of states, led by New York, said it was looking into Facebook, which has 1.5bn daily users across its products.
The firm settled for $5bn (£4bn) earlier this year after sharing data from 87m users with Cambridge Analytica, a political consultancy which counted the Trump campaign among its customers.
Google has come under scrutiny both in the US and in Europe, for claims it promotes its own products on its ubiquitous search engine. Competitors claim this unfairly hurts their business.
According to the Wall Street Journal, the US Department of Justice has its own antitrust probe into the firm.
Google said on Friday it had not yet been contacted by antitrust authorities in the states. But it promised to work with them.
Shares in Google parent Alphabet were trading down around 0.7 per cent.