A class action alleges two traders manipulated California’s gas prices to the tune of $2.4 billion.

The antitrust lawsuit, filed on Wednesday, comes after California Attorney General Xavier Becerra filed a similar case earlier this month against the same two trading companies, who he accused of violating California unfair competition law by manipulating the “spot market” for wholesale gasoline and gasoline blending products following an Exxon Mobil refinery explosion in 2015 in Torrance, California. The refinery supplied about 10% of the gasoline in California.