29 C.F.R. § 4041.26 – PBGC review of standard termination notice.

(a) Review period—(1) In general. The PBGC will notify the plan administrator in writing of the date on which it received a complete standard termination notice at the address provided in the PBGC's standard termination forms and instructions package. If the PBGC does not issue a notice of noncompliance under § 4041.31 during its 60-day review period following such date, the plan administrator must proceed to close out the plan in accordance with § 4041.28.
(2) Extension of review period. The PBGC and the plan administrator may, before the expiration of the PBGC review period in paragraph (a)(1) of this section, agree in writing to extend that period.
(b) If standard termination notice is incomplete—(1) For purposes of timely filing. If the standard termination notice is incomplete, the PBGC may, based on the nature and extent of the omission, provide the plan administrator an opportunity to complete the notice. In such a case, the standard termination notice will be deemed to have been complete as of the date when originally filed for purposes of § 4041.25(a), provided the plan administrator provides the missing information by the later of—
1. (i) The 180th day after the proposed termination date; or
2. (ii) The 30th day after the date of the PBGC notice that the filing was incomplete.
3. (2) For purposes of PBGC review period. If the standard termination notice is completed under paragraph (b)(1) of this section, the PBGC will determine whether the notice will be deemed to have been complete as of the date when originally filed for purposes of determining when the PBGC's review period begins under § 4041.26(a)(1).
(c) Additional information—(1) Deadline for providing additional information. The PBGC may in any case require the submission of additional information relevant to the termination proceeding. Any such additional information becomes part of the standard termination notice and must be submitted within 30 days after the date of a written request by the PBGC, or within a different time period specified therein. The PBGC may in its discretion shorten the time period where it determines that the interests of the PBGC or participants may be prejudiced by a delay in receipt of the information.
(2) Effect on termination proceeding. A request for additional information will suspend the running of the PBGC's 60-day review period. The review period will begin running again on the day the required information is received and continue for the greater of—
1. (i) The number of days remaining in the review period; or
2. (ii) Five regular business days.