California’s Monopolization Act Passes Go: COMPETE Act Takes Effect January 1, 2027

On September 30, 2026, California Governor Gavin Newsom formally signed Assembly Bill 1776, widely recognized as the Competition and Opportunity in Markets for a Prosperous, Equitable and Transparent Economy (COMPETE) Act. Scheduled to take effect on January 1, 2027, this landmark legislation fundamentally alters the state’s antitrust landscape by amending the historic Cartwright Act to reach single-firm conduct. While legislative negotiations successfully pared back some of the bill’s more contentious provisions prior to its final passage, the new law arms the California Attorney General and local district attorneys with a powerful, modernized instrument to aggressively pursue monopolistic and monopsonistic practices across the state.

The enactment of the COMPETE Act represents a watershed moment in state-level antitrust enforcement. For decades, federal enforcement under Section 2 of the Sherman Act served as the primary legal mechanism for policing single-firm abuses, such as unlawful maintenance of monopoly power, exclusionary practices, and anticompetitive acquisitions. With the arrival of AB 1776, California has created a parallel and potentially more aggressive state-level framework. As businesses prepare for the statute’s implementation, corporate legal departments, compliance officers, and executive leadership are scrambling to understand the profound operational and litigation risks introduced by the legislation.

Background and Legislative Evolution

The journey of AB 1776 through the California State Legislature was marked by intense debate, heavy lobbying from both corporate interests and consumer advocacy groups, and significant amendments. The Cartwright Act, originally enacted in 1907, traditionally focused on multi-firm conspiracies, cartels, and horizontal or vertical restraints of trade. It did not traditionally encompass unilateral conduct by a single dominant market participant unless that conduct was tied to a conspiracy with another entity.

Recognizing perceived gaps in federal enforcement and a desire to crack down on dominant technology platforms, healthcare networks, and massive retail entities operating within its borders, California lawmakers sought to bridge this divide. The introduction of the COMPETE Act sought to explicitly prohibit monopolization, monopsonization, and any attempts or conspiracies to monopolize or monopsonize any part of trade or commerce within the state.

Although earlier drafts of the bill included provisions that drew sharp criticism from business coalitions—such as sweeping presumptions of market power and pathways for expansive private rights of action—subsequent compromises helped streamline the text. Notably, the final version enacted by Governor Newsom excludes private enforcement mechanisms, meaning lawsuits under the expanded single-firm provisions will be the exclusive purview of public enforcers, including the California Attorney General’s office and local district attorneys. However, the absence of private lawsuits does little to comfort major corporations, given the aggressive enforcement posture historically maintained by California’s top law enforcement officials.

The Regulatory Timeline: From Bill to Implementation

Understanding the trajectory of AB 1776 requires examining the chronological milestones that brought California to this juncture. The timeline reflects a coordinated push by state lawmakers to rewrite California’s competition laws in response to modern economic challenges.

• Early 2026: Assembly Bill 1776 is introduced in the California State Assembly, drawing immediate national attention for its ambitious attempt to criminalize or penalize single-firm monopolization at the state level.
• Spring and Summer 2026: Legislative committees review the bill amid intense lobbying. Economic analysts, antitrust practitioners, and business associations express concern over potential conflicts with federal antitrust jurisprudence and the creation of regulatory uncertainty.
• Late August 2026: Lawmakers amend the bill to remove several polarizing provisions, notably scaling back certain private right of action components while retaining robust enforcement authority for public prosecutors.
• September 11, 2026: The California State Legislature officially passes AB 1776, sending the measure to the Governor’s desk.
• September 30, 2026: Governor Gavin Newsom signs the COMPETE Act into law, issuing an accompanying signing statement that emphasizes the state’s commitment to fostering a fair, equitable, and transparent marketplace.
• January 1, 2027: The statutory amendments take effect, formally expanding the Cartwright Act to cover single-firm monopolization and monopsonization.

Intersection with Other California Antitrust Reforms

The COMPETE Act does not exist in a vacuum; it arrives alongside a wave of recent legislative activity designed to tighten California’s grip on anticompetitive behavior. Most notably, AB 325 recently modified the Cartwright Act to introduce strict liability for algorithmic pricing. Under AB 325, companies face liability for agreements that use or distribute a common pricing algorithm as part of a contract, combination, or conspiracy to restrain trade. Furthermore, the law penalizes entities that coerce others into accepting prices or commercial terms recommended by common pricing algorithms for similar products.

When combined with the COMPETE Act’s prohibition on single-firm monopolization, these concurrent statutes create a multi-layered regulatory matrix. A dominant firm utilizing sophisticated, algorithmic pricing models could theoretically face scrutiny under both single-firm monopolization theories (if their algorithms serve to exclude competitors or consolidate market dominance) and traditional multi-firm conspiracy theories (if the algorithm is deemed to facilitate tacit coordination among market participants).

Legal Implications and Compliance Challenges

The expansion of the Cartwright Act to encompass unilateral conduct introduces distinct challenges for enterprises doing business in California. Historically, California courts have interpreted state antitrust laws independently from federal precedents in certain contexts, often emphasizing broader consumer protection goals. This divergence creates legal uncertainty.

For instance, federal antitrust law under the Sherman Act requires plaintiffs to meet rigorous standards regarding relevant market definition, market power thresholds, and anticompetitive effects, while balancing pro-competitive justifications under the rule of reason. It remains to be seen how California state courts will interpret these same elements under the newly expanded Cartwright Act. Will state courts adopt established federal jurisprudence under Section 2, or will they forge a distinct path that lowers the bar for state prosecutors?

Furthermore, the statute’s application to monopsonization—the abuse of buyer power—places heavy scrutiny on large employers, dominant retail buyers, and agricultural purchasers. Companies that wield significant purchasing power in labor markets or supply chains could find their standard procurement and wage-setting practices targeted by state enforcers claiming that the firm is unfairly suppressing wages or squeezing suppliers.

Official Responses and Stakeholder Perspectives

The enactment of AB 1776 has drawn sharply divided reactions from legal experts, consumer advocates, and business organizations.

Proponents of the legislation, including consumer protection groups and labor advocates, view the COMPETE Act as an essential and long-overdue modernization of state law. Supporters argue that federal antitrust enforcement has historically been too slow or under-resourced to effectively police modern corporate behemoths, particularly in the digital economy. By empowering the Attorney General and district attorneys, proponents believe California can effectively deter predatory pricing, exclusionary bundling, and other monopolistic practices that harm local businesses, workers, and consumers.

Conversely, business and industry coalitions have expressed deep concern over the compliance burdens and legal risks introduced by the statute. Representatives from technology, retail, and manufacturing sectors argue that the vague statutory definitions and the potential for expansive interpretations by state prosecutors could chill pro-competitive business behavior. Companies may hesitate to engage in aggressive discounting, exclusive distribution arrangements, or intellectual property licensing out of fear that standard business practices will be recharacterized by state enforcers as illegal monopolization attempts.

Strategic Takeaways for Businesses Operating in California

Although the COMPETE Act currently excludes private class action litigation—thereby mitigating the immediate threat of private treble-damages lawsuits—enterprises with substantial operations and significant market share in California must act proactively. Because the California Attorney General and motivated district attorneys are expected to utilize the new statute aggressively, companies should immediately initiate the following compliance and risk-mitigation measures:

1. Conduct Comprehensive Market Share and Power Assessments: Organizations must evaluate their market position across all relevant product and geographic markets within California. Identifying areas where the firm holds a dominant share or significant buyer power is the first step in assessing vulnerability under the new law.

2. Review Unilateral Commercial Practices: Legal and compliance teams should audit single-firm practices that could attract regulatory scrutiny. This includes examining exclusive dealing contracts, loyalty rebates, tying and bundling arrangements, and restrictive distribution agreements.

3. Scrutinize Pricing Strategies and Algorithms: In light of both the COMPETE Act and AB 325, companies must closely monitor their pricing mechanisms. The use of automated pricing software, algorithmic tools, and shared market data should be rigorously evaluated to ensure they do not create exposure under either single-firm monopolization or algorithmic collusion theories.

4. Enhance Antitrust Compliance Training: Corporate training programs must be updated to educate sales, marketing, and executive leadership teams on the expanded scope of California antitrust law. Employees must understand that unilateral conduct—even absent an explicit agreement with a competitor—can now trigger severe state-level enforcement actions.

Conclusion

As the January 1, 2027 effective date approaches, the COMPETE Act stands out as one of the most significant state-level regulatory developments in modern U.S. antitrust history. By filling perceived gaps in federal enforcement and equipping public prosecutors with robust tools to police single-firm conduct, California has cemented its role as a pioneering regulator of corporate behavior. For businesses operating within the Golden State, navigating this new era will require meticulous compliance, heightened vigilance, and a proactive approach to managing regulatory risk.