The U.S. Supreme Court on Thursday declined to block enforcement of an anti-money laundering law that forces millions of business entities to disclose the identities of their real beneficial owners to the Treasury Department,

The Corporate Transparency Act, which requires businesses to disclose ownership information, was blocked by a federal judge as beyond Congress’s authority.

Owners and part-owners of an estimated 32.6 million small businesses must register personal information with Treasury’s Financial Crimes Enforcement Network, or FinCEN.