Under siege for setting up thousands of phony customer accounts to generate fees, Wells Fargo has taken a beating in Congress and the court of public opinion. Several states have piled on, announcing that they are temporarily cutting their business ties with the bank.

Using the power of the purse to hold a wayward behemoth to account is a good thing. But if state officials want to teach financial firms a lesson in honesty, why stop at Wells Fargo?

Many other big players in finance need this kind of instruction, too. For example, securities regulators have accused some of the nation’s top private equity firms of putting their interests ahead of their clients’. Why don’t state pension officials refuse to do business with them?

Consider a case involving Apollo Global Management, the private equity giant overseen by Leon Black. In late August, the Securities and Exchange Commission brought an enforcement action against the firm, contending that it had breached its fiduciary duty to investors by not disclosing specifics on fees it was extracting. The suit followed other improper fee cases filed by the S.E.C. against the Blackstone Group and KKR.