California’s COMPETE Act Sets New Single‑Firm Antitrust Regime Effective 2027

The California Competition and Opportunity in Markets for a Prosperous, Equitable and Transparent Economy Act (COMPETE Act) is slated to take effect on January 1 2027. It establishes a new single‑firm antitrust regime that will apply to companies operating within California, regardless of their size, and imposes stricter scrutiny on market‑dominant conduct, pricing, and mergers that could harm competition. Key provisions include expanded investigatory authority for the Office of Attorney General, higher penalties for non‑compliance, and mandatory reporting of market‑share data. For firms with substantial California operations—especially in tech, retail, and financial services—the act requires a thorough audit of existing market‑share practices and potential black‑spot deals. The compliance burden extends to any mergers or acquisitions that create a de facto monopoly in the state’s markets. Counsel should review current market‑share disclosures and prepare remediation plans to mitigate exposure by 2026. Firms will also need to reevaluate post‑merger integration strategies to align with the new regulatory expectations that could significantly elevate enforcement risks in California.