This bill amends California’s Cartwright Act to introduce new regulations around pricing algorithms and antitrust violations. Specifically, the bill prohibits the use or distribution of pricing algorithms that incorporate nonpublic competitor data, and establishes legal presumptions that can be used against defendants who engage in such practices. If a court finds a violation, it can presume that the defendant entered into an anti-competitive contract or trust, with these presumptions applying if the defendant distributed a pricing algorithm to multiple parties with the intent of influencing pricing, or used such an algorithm to set prices in a market. The bill also modifies legal complaint requirements, stating that a complaint alleging Cartwright Act violations only needs to demonstrate the plausible existence of an anti-competitive contract or conspiracy, without having to definitively prove that independent action was impossible. The bill provides detailed definitions for key terms like “pricing algorithm,” “nonpublic competitor data,” and “commercial terms,” and includes provisions that ensure the bill does not impair existing antitrust laws. Because the bill expands prohibited activities under the Cartwright Act, it is considered a state-mandated local program, though the bill specifies that no reimbursement is required for implementing its provisions.