29 CFR § 4050.205 - Filing with PBGC.
(2) Any fee provided for in the missing participants forms and instructions.
(c) Place, method and date of filing; time periods.
(1) For rules about where to file, see § 4000.4 of this chapter.
(d) Supplemental information. Within 30 days after a written request by PBGC (or such other time as may be specified in the request), the plan administrator of a subpart B plan required to file under paragraph (a) of this section must file with PBGC supplemental information for any proper purpose under the missing participants program.