Cal. Welfare and Institutions Code § 14199.83

(a) The department shall determine for each health plan, using the base data source, all of the following: (1) Total cumulative enrollment for the base year. (2) Total Medicare cumulative enrollment for the base year. (3) Total Medi-Cal cumulative enrollment for the base year. (4) Total plan-to-plan cumulative enrollment for the base year. (5) Total cumulative enrollment through the Federal Employees Health Benefits Act of 1959 (Public Law 86-382) for the base year. (6) Total other cumulative enrollment for the base year that is not otherwise counted in paragraphs (2) to (5), inclusive. (b) Notwithstanding any other provision in this article, the director may correct any identified material or significant error in the data, including, but not limited to, the overall cumulative enrollment, Medicare cumulative enrollment, Medi-Cal cumulative enrollment, plan-to-plan cumulative enrollment, cumulative enrollment through the Federal Employees Health Benefits Act of 1959 (Public Law 86-382), and other cumulative enrollment. The director’s determination as to whether to exercise discretion under this section and any determination made by the director under this section shall not be subject to judicial review, except that a health plan may bring a writ of mandate under Section 1085 of the Code of Civil Procedure to rectify an abuse of discretion by the department in correcting that health plan’s data when that correction results in a greater tax amount for that health plan pursuant to Section 14199.85.