Cal. Lab. Code § 4609
(b) Beginning July 1, 2000, every contracting agent that sells, leases, assigns, transfers, or conveys its list of contracted health care providers and their contracted reimbursement rates to a payor, as defined in subparagraph (A) of paragraph (3) of subdivision (d), or another contracting agent shall, upon entering or renewing a provider contract, do all of the following:
(5) Allow providers, upon the initial signing, renewal, or amendment of a provider contract, to decline to be included in any list of contracted providers that is sold, leased, transferred, or conveyed to payors that do not actively encourage the employees to use the list of contracted providers when obtaining medical care as described in paragraph (2). Each provider’s election under this paragraph shall be binding on the contracting agent with which the provider has the contract and any other contracting agent that buys, leases, or otherwise obtains the list of contracted providers.
A provider shall not be excluded from any list of contracted providers that is sold, leased, transferred, or conveyed to payors that actively encourage the employees to use the list of contracted providers when obtaining medical care, based upon the provider’s refusal to be included on any list of contracted providers that is sold, leased, transferred, or conveyed to payors that do not actively encourage the employees to use the list of contracted providers when obtaining medical care.
(6) If the payor’s explanation of benefits or explanation of review does not identify the name of the network that has a written agreement signed by the provider whereby the payor is entitled, directly or indirectly, to pay a preferred rate for the services rendered, the contracting agent shall do the following:
(c) Beginning July 1, 2000, a payor, as defined in subparagraph (B) of paragraph (3) of subdivision (d), shall do all of the following:
(2) Demonstrate that it is entitled to pay a contracted rate within 30 business days of receipt of a written request from a provider who has received a claim payment from the payor. The provider shall include in the request a statement explaining why the payment is not at the correct contracted rate for the services provided. The failure of the provider to include a statement shall relieve the payor from the responsibility of demonstrating that it is entitled to pay the disputed contracted rate. The failure of a payor to make the demonstration to a properly documented request of the provider within 30 business days shall render the payor responsible for the lesser of the provider’s actual fee or, as applicable, any fee schedule pursuant to this division, which amount shall be due and payable within 10 days of receipt of written notice from the provider, and shall bar the payor from taking any future discounts from that provider without the provider’s express written consent until the payor can demonstrate to the provider that it is entitled to pay a contracted rate as provided in this subdivision. A payor shall be deemed to have demonstrated that it is entitled to pay a contracted rate if it complies with either of the following:
(d) For the purposes of this section, the following terms have the following meanings:
(3)
(5) “Provider” means any of the following: