Wash. Rev. Code § 48.08.110
Every person who is directly or indirectly the beneficial owner of more than ten percent of any class of any equity security of a domestic stock insurer, or who is a director or an officer of such insurer, shall file with the commissioner on or before the 30th day of September, 1965, or within ten days after he or she becomes such beneficial owner, director or officer, a statement, in such form as the commissioner may prescribe, of the amount of all equity securities of such insurer of which he or she is the beneficial owner, and within ten days after the close of each calendar month thereafter, if there has been a change in such ownership during such month, shall file with the commissioner a statement, in such form as the commissioner may prescribe, indicating his or her ownership at the close of the calendar month and such changes in his or her ownership as have occurred during such calendar month.
RCW 48.08.110