Overview

• As of July 27, 2025, parties with federal HSR-reportable transactions and sufficient ties to Washington must submit their filings to the Washington attorney general under the state’s new Antitrust Premerger Notification Act.
• Colorado’s counterpart law takes effect on August 6, 2025, requiring companies with a principal place of business in the state or at least $25.3 million in annual in-state sales to file their HSR forms with the Colorado attorney general.
• Neither statute imposes filing fees or suspends the deal-closing process, but both authorize daily civil penalties for noncompliance.
• Submissions are exempt from state public records laws and may only be shared with federal agencies or other state attorneys general under confidentiality safeguards.
• California, the District of Columbia, Hawaii, Nevada and West Virginia are advancing similar bills as part of a broader shift toward proactive state-level antitrust enforcement.