Pub. L. 93-406, tit. IV, subtit. D, sec. 4066
annual notification to substantial employers
annual notification to substantial employers Sec. 4066. The plan administrator of each plan under which contributions are made by more than one employer shall notify, within 6 months after the close of each plan year, any employer making contributions under that plan who is described in section 4001(a)(2) that he is a substantial employer for that year.