On June 4, Colorado became the second state to adopt the Uniform Antitrust Premerger Notification Act (Act) when Governor Jared Polis signed SB25-126 into law. Like Washington’s version of the Act, Colorado’s new law imposes state-level premerger filing obligations for certain transactions already reportable under the federal Hart-Scott-Rodino (HSR) Act. The law reflects a broader shift toward increased state scrutiny of mergers and acquisitions and signals the growing complexity of multijurisdictional antitrust compliance.
Hart-Scott-Rodino (HSR) Act
Under the federal HSR Antitrust Improvements Act of 1976, parties to transactions that exceed a minimum size threshold—set at $126.4 million for 2025—must file a premerger notification with the Federal Trade Commission (FTC) and Department of Justice (DOJ) and observe a mandatory waiting period prior to closing. The purpose of the HSR regime is to allow federal agencies to assess the potential competitive impact of a transaction before consummation.
Key Provisions of Colorado’s Act
Colorado’s new law requires parties to submit a copy of their federal HSR filing to the Colorado Attorney General (AG) if at least one of the following criteria is met:
- A party has annual net sales in Colorado of 20% or more of the HSR threshold (i.e., $25.3 million for 2025).
- A party has its principal place of business in Colorado.
Like the Washington law, Colorado’s Act does not impose a separate state filing fee or waiting period. Transactions may proceed during the Colorado AG’s review. However, failure to comply with the law may result in civil penalties of up to $10,000 per day.
The new requirements will likely take effect later this year, unless there is a petition to have the act approved by ballot measure, in which case it will not take effect until after the November 2026 elections.
Uniform Premerger Notification Act – State-Level Momentum Builds
The Colorado statute is based on the model Uniform Antitrust Premerger Notification Act developed by the Uniform Law Commission (ULC), which aims to promote consistency across states in merger notification requirements. Following Washington’s enactment of the Act in April 2025, Colorado is now the second state to pass legislation based on the model law. Similar bills remain under consideration in several other jurisdictions, including California, Hawaii, Nevada, Utah, West Virginia, and the District of Columbia.
In parallel, states such as New York and California are also weighing broader premerger notification regimes that extend beyond the model law’s structure.
Implications for Dealmakers
Colorado’s adoption of the Uniform Antitrust Premerger Notification Act underscores a growing trend toward more assertive and coordinated state-level merger enforcement. As more states enact similar laws, parties to HSR-reportable deals will increasingly need to evaluate whether parallel state filings are required.
Transaction planning will need to incorporate additional diligence to identify applicable state-level obligations early and to avoid costly delays or penalties. Dealmakers should work closely with antitrust counsel to monitor evolving state requirements and adjust timelines and strategies accordingly.
