Google has another antitrust probe to worry about, after 50 attorneys general said on Monday they’re opening a collective investigation into the tech giant’s dominance of online advertising.

The investigation is being spearheaded by Texas attorney general Ken Paxton; it includes all states except for California and Alabama, as well as Puerto Rico and the District of Columbia. Paxton announced the investigation on the steps of the Supreme Court in Washington, D.C. on Monday.

“[Google] is a company that dominates all aspects of advertising on the internet and searching on the internet as they dominate the buyers’ side, the sellers’ side, the auction side and even the video side with YouTube,” Paxton said, according to The Hill. “This is an investigation to determine the facts, and right now we’re looking at advertising. But the facts will lead to where the facts lead.”

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Google did not immediately respond to TheWrap’s request for comment.

The Mountain View, California-based company reported in July that it made $32.6 billion in revenue from its ad business during the second quarter. Its stock price was down 0.2% near the end of trading on Monday, hitting $1,203 per share.

The probe comes as Google and other Silicon Valley stalwarts are facing increasing scrutiny from lawmakers and regulators, including an antitrust review from the Justice Department. Last week, Google-owned platform YouTube paid a record-setting $170 million settlement for collecting personal information on children without their parents’ consent.

Facebook is also facing a similar antitrust investigation, with New York State Attorney General Letitia James opening a multi-state probe into the company’s business practices last week.

Despite the added pressure from Washington, antitrust experts recently told TheWrap that the breakup of major tech firms is anything but a sure thing. Penn State antitrust professor John Lopatka said there are “two necessary ingredients” that would be needed to take action against companies like Facebook and Google: Not only does there have to be proof Facebook and Google are monopolies, but you’d also have to show they extended their monopoly “through anti-competitive conduct.”

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