16 CFR § 4.3 - Time.
(a) Computation. Computation of any period of time prescribed or allowed by the rules in this chapter, by order of the Commission or an Administrative Law Judge, or by any applicable statute, shall begin with the first business day following that on which the act, event, or development initiating such period of time shall have occurred. When the last day of the period so computed is a Saturday, Sunday, or national holiday, or other day on which the office of the Commission is closed, the period shall run until the end of the next following business day. When such period of time, with the intervening Saturdays, Sundays, and national holidays counted, is seven (7) days or less, each of the Saturdays, Sundays, and such holidays shall be excluded from the computation. When such period of time, with the intervening Saturdays, Sundays, and national holidays counted, exceeds seven (7) days, each of the Saturdays, Sundays, and such holidays shall be included in the computation.
(b) Extensions. For good cause shown, the Administrative Law Judge may, in any proceeding before him or her: (1) Extend any time limit prescribed or allowed by order of the Administrative Law Judge or the Commission (if the Commission order expressly authorizes the Administrative Law Judge to extend time periods); or (2) extend any time limit prescribed by the rules in this chapter, except those governing motions directed to the Commission, interlocutory appeals and initial decisions and deadlines that the rules expressly authorize only the Commission to extend. Except as otherwise provided by law, the Commission, for good cause shown, may extend any time limit prescribed by the rules in this chapter or by order of the Commission or an Administrative Law Judge, provided, however, that in a proceeding pending before an Administrative Law Judge, any motion on which he or she may properly rule shall be made to the Administrative Law Judge. Notwithstanding the above, where a motion to extend is made after the expiration of the specified period, the motion may be considered where the untimely filing was the result of excusable neglect.
(c) Additional time after certain kinds of service. Whenever a party in an adjudicative proceeding under part 3 of this chapter is required or permitted to do an act within a prescribed period after service of a document upon it and the document is served by first-class mail pursuant to § 4.4(a)(2) or (b), 3 days shall be added to the prescribed period. Whenever a party in an adjudicative proceeding under part 3 is required or permitted to do an act within a prescribed period after service of a document upon it and the document is served by electronic delivery pursuant to § 4.4(e), 1 day shall be added to the prescribed period.
(d) Date of filing. Documents permitted to be filed using the electronic filing system must be received by 11:59 p.m. Eastern Time to be deemed timely filed that day. All other documents must be received in the Office of the Secretary by 5:00 p.m. Eastern Time to be deemed filed that day, and any such document received after 5:00 p.m. Eastern Time will be deemed filed the following business day.