29 C.F.R. § 2520.104a-9

(a) General. A defined contribution group (DCG) reporting arrangement described in § 2520.104-51(c) that files a consolidated annual report for all the plans participating in the DCG reporting arrangement in accordance with the terms of paragraphs (b) and (c) of this section shall be deemed to have filed such a report in accordance with § 2520.104a-9 for purposes of § 2520.104-51.

(b) Date of filing. The consolidated annual report shall be filed within seven months after the close of the common plan year of all the plans participating in the DCG reporting arrangement, unless extended. See “When to file” instructions of the Form 5500 Annual Return/Report.

(c) Where to file. The consolidated annual report prescribed in § 2520.103-14 shall be filed electronically in accordance with the instructions to the Annual Return/Report Form.