Major energy producers Texas and West Virginia are leading a lawsuit against BlackRock, State Street, and Vanguard, alleging manipulation of the energy market against coal power. The lawsuit claims that these firms have facilitated an “output reduction scheme, which has artificially constrained the supply of coal.”

The lawsuit alleges smaller coal producers weren’t able to raise production and sufficiently meet demand in order to keep a share of the market.

BlackRock and State Street dispute the claims made by the attorneys general regarding competition restraint.