California Code, Health and Safety Code - HSC § 1367.2075

(a) A health care service plan contract issued, amended, or renewed on or after January 1, 2026, that provides prescription drug coverage shall not calculate an enrollee's cost sharing at an amount that exceeds the actual rate paid by the plan for the prescription drug, and shall include cost-sharing provisions consistent with Section 4079 of the Business and Professions Code.  Cost sharing shall include deductibles and copayments.

(b) To the extent that a health care service plan contract with a pharmacy benefit manager issued, amended, or renewed on or after January 1, 2026, includes disclosure on the net price paid by the pharmacy benefit manager or group purchasing organization, then an enrollee's cost share shall not be calculated at an amount that exceeds that net price paid.