Every person who, on December 31, 1965, is directly or indirectly the beneficial owner of more than 10 percent of any class of equity security of a domestic stock insurance company, or who is a director or an officer of such company, and every person who becomes such a beneficial owner, director, or officer after that date shall file in the office of the commissioner on or before January 10, 1966, or within 10 days after he becomes such beneficial owner, director, or officer, whichever date is later, a statement in such form as the commissioner may prescribe, of the amount of all equity securities of such company of which he is the beneficial owner. Within 10 days after the close of each calendar month thereafter, if there has been a change in such ownership during such month, he shall file in the office of the commissioner a statement, in such form as the commissioner may prescribe, indicating his ownership at the close of the calendar month and such changes in his ownership as have occurred during such calendar month.