Texas Attorney General Ken Paxton had joined the US Justice Department’s lawsuit against the company in October.
“Google repeatedly used its monopolistic power to control pricing (and) engage in market collusions to rig auctions in a tremendous violation of justice,” Paxton said in a Facebook video.
Google “eliminated its competition and crowned itself the king of online advertising,” he added.
The Texas lawsuit is the fourth in a series of federal and state lawsuits aimed at reining in what is alleged to be bad behavior by the big tech platforms that have grown from nothing to titans in the past two decades. The lawsuit was filed in the Eastern District of Texas.
The nine states that joined Texas are Arkansas, Indiana, Kentucky, Missouri, Mississippi, South Dakota, North Dakota, Utah and Idaho.
Alphabet shares added slightly to losses to trade down 0.5% on Wednesday afternoon after news of the new lawsuit.