15 CFR 766.10: Subpoenas.

(a) Issuance. Upon the application of any party, supported by a satisfactory showing that there is substantial reason to believe that the evidence would not otherwise be available, the administrative law judge will issue subpoenas requiring the attendance and testimony of witnesses and the production of such books, records or other documentary or physical evidence for the purpose of the hearing, as the judge deems relevant and material to the proceedings, and reasonable in scope.

(b) Service. Subpoenas issued by the administrative law judge may be served in any of the methods set forth in § 766.5(b) of this part.

(c) Timing. Applications for subpoenas must be submitted at least 10 days before the scheduled hearing or deposition, unless the administrative law judge determines, for good cause shown, that extraordinary circumstances warrant a shorter time.