California Code, Health and Safety Code - HSC § 1348.95

(a) Commencing March 1, 2013, and at least annually thereafter, a health care service plan, not including a health care service plan offering specialized health care service plan contracts, shall provide to the department, in a form and manner determined by the department in consultation with the Department of Insurance, the number of enrollees, by product type, as of December 31 of the prior year, that receive health care coverage under a health care service plan contract that covers individuals and small groups inside and outside of the California Health Benefit Exchange, large groups, administrative services only business lines, and any other business lines. Health care service plans shall include the enrollment data in specific product types as determined by the department, including, but not limited to, HMO, point-of-service, PPO, grandfathered, and Medi-Cal managed care. Data reported pursuant to this subdivision shall specify the covered persons that are being reported pursuant to subdivision (b).

(b) Commencing March 1, 2020, and at least annually thereafter, a health care service plan that provides coverage through a multiple employer welfare arrangement (MEWA) that is not subject to Article 4.7 (commencing with Section 742.20) of Chapter 1 of Part 2 of Division 1 of the Insurance Code shall provide to the department, in a form and manner determined by the department in consultation with the Department of Insurance, the name of each MEWA and the number of covered persons in each MEWA as of December 31 of the prior year, divided by market segment and product type. Data reported pursuant to this subdivision shall be identified and separately reported under subdivision (a).

(c) The department shall publicly report the data provided by each health care service plan pursuant to this section, including, but not limited to, posting the data on the department's internet website. The department shall consult with the Department of Insurance to ensure that the data reported is comparable and consistent, does not duplicate existing reporting requirements, and utilizes existing reporting formats. The data for the previous calendar year shall be made available no later than April 15 of each calendar year.