Cal. Ins. Code § 10133.64

(a) A contract issued, amended, renewed, or delivered on or after January 1, 2015, by or on behalf of a health insurer and a provider or supplier shall not contain any provision that restricts the ability of the health insurer to furnish consumers or purchasers information concerning any of the following:
1. (1) The cost range of a procedure or a full course of treatment, including, but not limited to, facility, professional, and diagnostic services, prescription drugs, durable medical equipment, and other items and services related to the treatment.
2. (2) The quality of services performed by the provider or supplier.
(b) Any contractual provision inconsistent with this section shall be void and unenforceable.
(c) A health insurer shall provide the provider or supplier an advance opportunity of 30 days to review the methodology and data developed and compiled by the health insurer, and used pursuant to subdivision (a), before cost or quality information is provided to consumers or purchasers, including material revisions or additions of new information. At the time the health insurer provides a provider or supplier with the opportunity to review the methodology and data, it shall also notify the provider or supplier in writing of their opportunity to provide an Internet Web site link pursuant to subdivision (f).
(d) If the information proposed to be furnished to policyholders and insureds on the quality of services performed by a provider or supplier is data that the insurer has developed and compiled, the insurer shall utilize appropriate risk adjustment factors to account for different characteristics of the population, such as case mix, severity of patient’s condition, comorbidities, outlier episodes, and other factors to account for differences in the use of health care resources among providers and suppliers.
(e) Any Internet Web site owned or controlled by a health insurer, or operated by another person or entity under contract with or on behalf of a health insurer, that displays the information developed and compiled by the health insurer as referenced by this section shall prominently post the following statement:
“Individual health care facilities or providers may disagree with the methodology used to define the cost ranges, the cost data, or quality measures. Many factors may influence cost or quality, including, but not limited to, the cost of uninsured and charity care, the type and severity of procedures, the case mix of a facility, special services such as trauma centers, burn units, medical and other educational programs, research, transplant services, technology, payer mix, and other factors affecting individual health care facilities and providers.”
A health insurer and a provider or supplier shall not be precluded from mutually agreeing in writing to an alternative method of conveying this statement.
(f) If a provider or supplier chooses to provide an Internet Web site link where a response to the health insurer’s posting may be found, it shall do so in a timely manner in order to satisfy the requirements of this section. If a provider or supplier chooses to provide a response, an insurer shall post, in an easily identified manner, a prominent link to the provider’s or supplier’s Internet Web site where a response to the health insurer’s posting may be found. A health insurer and a provider or supplier shall not be precluded from mutually agreeing in writing to an alternative method to convey a provider’s or supplier’s response.
(g) For the purposes of this section, the following definitions shall apply:
1. (1) “Consumers” means policyholders or insureds of the health insurer or beneficiaries of a self-funded health coverage arrangement administered by the health insurer or other persons entitled to access services through a network established by the health insurer.
2. (2) “Provider” has the same meaning as that term is defined in Section 10117.52.
3. (3) “Purchasers” means the sponsors of a self-funded health coverage arrangement administered by the health insurer.
4. (4) “Supplier” has the same meaning as that term is defined in Section 10117.52.