Existing law, the Knox-Keene Health Care Service Plan Act of 1975, provides for the licensure and regulation of health care service plans by the Department of Managed Health Care and makes a willful violation of the act a crime. Existing law provides for the regulation of health insurers by the Department of Insurance. Existing law requires a health insurer or health care service plan, including a specialized health care service plan, to reimburse a claim or portion of a claim no later than 30 working days after receipt of the claim, unless the plan contests or denies the claim, in which case the plan is required to notify the claimant within 30 working days that the claim is contested or denied. Under existing law, if a claim or portion thereof is contested on the basis that a health insurer or health care service plan has not received all information necessary to determine payer liability for the claim or portion thereof and notice has been provided, the health insurer or health care service plan has 30 working days after receipt of the additional information to complete reconsideration of the claim. Existing law extends these timelines to 45 working days for a health care service plan that is a health maintenance organization. Under existing law, if a claim is not reimbursed, contested, or denied pursuant to these timelines, as specified, interest accrues at a rate of 15% per annum for a health care service plan and 10% per annum for a health insurer. Commencing January 1, 2026, this bill instead would require a health care service plan, including a Medi-Cal managed care plan, or health insurer to reimburse a complete claim or a portion thereof within 30 calendar days after receipt of the claim, or, if a claim or portion thereof does not meet the criteria for a complete claim or portion thereof, to notify the claimant as soon as practicable, but no later than 30 calendar days that the claim or portion thereof is contested or denied. The bill would authorize the departments to issue guidance and regulations related to these provisions. The bill would exempt the guidance and amendments from the Administrative Procedure Act until December 31, 2027. Existing law requires health care service plans to establish a grievance process, as specified. This bill would require a complaint made by an enrollee to a health care service plan about a delay or denial of a payment of a claim to be treated as a grievance subject to that grievance process. Because a willful violation of these provisions by a health care service plan would be a crime, the bill would impose a state-mandated local program. The California Constitution requires the state to reimburse local agencies and school districts for certain costs mandated by the state. Statutory provisions establish procedures for making that reimbursement. This bill would provide that no reimbursement is required by this act for a specified reason.