Cal. Ins. Code § 1104.2
Every person who is directly or indirectly the beneficial owner of more than 10 percent of any class of stock of a domestic insurer or who is a director or officer of such insurer shall file in the office of the Insurance Commissioner on or before the 31st day of October, 1965, or within 10 days after he becomes such a beneficial owner, director or officer, a statement, in such form as the commissioner may prescribe, of the amount of all stock of such insurer of which he is the beneficial owner, and within 10 days after the close of each calendar month thereafter, if there has been a change in such ownership during such month, shall file in the office of the commissioner a statement, in such form as the commissioner shall prescribe, indicating his ownership at the close of the calendar month and such changes in his ownership as have occurred during such calendar month.
Ca. Ins. Code § 1104.2