State antitrust enforcement is becoming increasingly significant, with a diverse array of laws across 51 jurisdictions, including the District of Columbia. State Attorneys General (AGs) are not merely filling gaps left by federal enforcement but are actively shaping the landscape with robust state-specific laws. This post provides an overview of the current trends and legislative developments in state antitrust enforcement that businesses need to be aware of as they assess their conduct and develop growth strategies.

State enforcement of federal and state laws

State AGs have the authority to bring federal antitrust suits on behalf of their residents or the state itself. They often collaborate with federal authorities and other states in antitrust investigations that affect their state. Indeed, it is not uncommon for several states to join existing federal investigations looking into proposed mergers or into business conduct that affect various states. And these actions are not strictly partisan as they involve AGs from both red and blue states.

National Association of Attorneys General (NAAG)

NAAG plays a crucial role in coordinating these efforts through its Multistate Task Force, which includes representatives from every state. The Task Force operates several committees and working groups focused on various industries and procedural issues. Notable groups include:

  • Agriculture Committee
  • Education and Training Committee
  • Energy Markets Working Group
  • Health Care Provider Committee
  • Labor and Antitrust Committee
  • Pharmaceutical Industry & PBM Working Group
  • Bid Rigging and Criminal Enforcement Committee (BRACE)

BRACE is a relatively new and notable committee as it provides a forum for 30 states to detect bid coordination particularly when directed at public contracts and foreclosure auctions. BRACE also coordinates issuance of state-level civil investigative demands and provides criminal prosecutorial training to enforcers. In February 2025, representatives from 14 states attended a BRACE-sponsored training in Chicago to improve state-level criminal prosecution of antitrust violations. BRACE has gained attention for its efforts in detecting bid coordination and providing criminal prosecutorial training.

State-specific antitrust actions

AGs also enforce state laws, often pursuing individual state actions when specific statutes apply or when the harm is localized. States can be a valuable resource for companies that have been victims of antitrust violations, offering more accessible and locally sensitive enforcement compared to federal counterparts.

Legislative developments

More than at any time in the past, states are proposing new competition-related legislation and creating their own review mechanisms that mirror and differ from those at the federal level. For instance, several states are advancing legislation on algorithmic pricing, with bills pending in at least 14 states, including Ohio, Arizona, California and New York. These bills aim to regulate or ban predictive pricing practices. Some, like California’s SB 52, would prohibit algorithmic pricing in particular situations, such as setting rental rates. Other bills, like Ohio’s SB 79, appear to seek an outright ban on predictive pricing. The varying approaches create the probability that companies will face different predictive pricing rules depending on where they conduct business.

Algorithmic pricing is not the only target of state legislative reform efforts. Just this month, Arkansas prohibited vertical integration between pharmacy benefit managers and pharmacies. A few states are pushing single-firm conduct legislation. New York’s SB 335 seeks, yet again to amend the Donnelly Act to address “abuse of dominance,” more akin to European Union competition law than to United States law under the Sherman Act. In California, watchers await the California Law Revision Commission’s (CLRC) proposed draft legislation on single-firm conduct after CLRC directed its staff in January 2025 to propose legislation addressing “standards . . . that guard against the misuse of market power.”

Pre-merger notification requirements

Pre-merger notification laws, or “Baby HSR” bills, are also gaining traction. States like Ohio and Washington already have such requirements for the healthcare industry, and other states, including California and Colorado, have pending legislation. Washington will be the first state to operate under the Uniform Antitrust Premerger Notification Act starting July 27, 2025.

Key takeaways

The landscape of state antitrust enforcement is evolving, with AGs gaining new tools and increasing their activity. Companies must stay informed about state legislative and NAAG initiatives to navigate this complex environment effectively.

  • Increased state enforcement: State AGs are becoming more active in antitrust enforcement, often collaborating on multistate actions. When thinking of potential enforcement, businesses now must consider whether the states will be interested, irrespective of federal involvement.
  • Diverse legislative landscape: States are enacting and considering various laws, including those targeting algorithmic pricing and vertical integration. Looking at federal law will no longer suffice and businesses must be aware that states may legislate against certain conduct in different ways.
  • Pre-merger notification: New pre-merger notification requirements are being implemented. Not only have the rules governing HSRs changed to require much more information, but merging parties may need to consider building in time to provide the appropriate notification under the “Baby HSRs.”

For further information or assistance, please contact our antitrust team.