For the purposes of any investigation provided for in this subchapter, the provisions of sections
49 and
50 of title
15 (relating to the attendance of witnesses and the production of books, records, and documents) are hereby made applicable (without regard to any limitation in such sections respecting persons, partnerships, banks, or common carriers) to the jurisdiction, powers, and duties of the Secretary or any officers designated by him. To the extent he considers appropriate, the Secretary may delegate his investigative functions under this section with respect to insured banks acting as fiduciaries of employee benefit plans to the appropriate Federal banking agency (as defined in section
1813
(q) of title
12).