(a) Methods of service. Service of a subpoena may be made by any of the methods identified in § 19.11(d).

(b) Expenses. The fees and expenses specified in § 19.14 apply to a witness who is subpoenaed to testify pursuant to this subpart.

(c) Area of service. Subpoenas issued in connection with a formal investigation proceeding that require the attendance and testimony of witnesses or the production of documents, including electronically stored information, may be served on any person or entity within any State, territory, or possession of the United States or the District of Columbia, or as otherwise provided by law. Foreign nationals are subject to such subpoenas if service is made upon a duly authorized agent located in the United States or in accordance with international requirements for service of subpoenas.