Limitation on most favored nation clauses
If a contract between a health care service plan and a provider requires that the provider accept, as payment from the plan, the lowest payment rate charged by the provider to any patient or third party, this contract provision shall not be deemed to apply to, or take into consideration, any cash payments made to the provider by individual patients who do not have any private or public form of health care coverage for the service rendered by the provider, as described in subdivision (c) of Section 657 of the Business and Professions Code. This section shall apply to a provider contract that is issued, amended, or renewed on or after the effective date of this section.
See https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=HSC§ionNum=1371.22.