California's COMPETE Act targets single-firm monopolization and monopsonization
Newsom signed the COMPETE Act on September 30, 2026, amending the Cartwright Act to reach single-firm monopolization and monopsonization, widening California exposure for dominant firms.
On September 30, 2026, California Governor Gavin Newsom signed the COMPETE Act into law, amending the state's antitrust statute, the Cartwright Act, to target single-firm monopolization and monopsonization conduct. California is one of a small number of US jurisdictions with a unilateral-conduct antitrust statute, so the bill is a significant expansion of the state's substantive reach beyond what federal law would ordinarily require a firm to face for exclusionary conduct directed at rivals or suppliers.
For major-firm clients, the immediate significance is that the conduct thresholds, burden-shifting structure, and available remedies under the amended statute may differ from the Section 2 framework applied elsewhere, including in any later parallel federal action. Antitrust counsel should expect renewed attention to pricing, exclusivity, non-compete, and buyer-power practices in California-facing transactions and commercial arrangements, particularly where a client holds dominant share in a narrow product or input market, or is a monopsonistic buyer.
The open items counsel will want to watch are the text of the enacted amendments and any accompanying statutory analysis, the Attorney General's and private enforcers' stated enforcement priorities, and whether the changes attract federal scrutiny or legislation in other states. Reported detail beyond the signing and subject matter should be verified against the signed chaptered text before being relied on.