Among its various attempts to regulate drug prices, the Trump administration recently sought to force pharmaceutical advertisements to disclose the wholesale acquisition cost (WAC) of certain drugs. This effort was dealt a setback in June, when the D.C. Circuit found that the Department of Health and Human Services (HHS) overstepped its regulatory authority by compelling disclosure of these costs. Merck & Co., Inc. v. U.S. Dep’t Health & Human Servs. (“Merck”). Although limited to a particular rule, the Merck decision foreshadows the likely future success of similar forced-disclosure rules.