17 C.F.R. § 12.12
(a) By whom. All documents filed with the Commission shall be signed personally:
(3) By an attorney-at-law having authority with respect thereto.
The Proceedings Clerk may require appropriate evidence of the authority of a person subscribing a document on behalf of another person.
(b) Effect. The signature on any document of any persons acting either for themselves or as attorney or agent for another constitutes certification by them that:
[49 FR 6621, Feb. 22, 1984, as amended at 86 FR 64352, Nov. 18, 2021]