Three of the largest investment shops in the U.S.—BlackRock, Vanguard and State Street—have long used their dominance in passive-investment funds to force corporations to comply with their preferred set of environmental, social and governance policies. Their reign, however, may be nearing its rightful end, as America’s law enforcers are waking up to the threats the Big Three pose to investors and the economy.

In an Aug. 4 letter to BlackRock CEO Larry Fink, 19 state attorneys general questioned how the company’s ESG advocacy squares with its fiduciary duties to investors. The attorneys general specifically raised whether BlackRock’s “coordinated conduct with other financial institutions”—i.e., the two other investing giants—to demonetize the oil-and-gas industry raises potential antitrust issues.