(a) A member shall make available to inspection by any bona fide regular customer, upon request, the information relative to such member's financial condition as disclosed in its most recent balance sheet prepared either in accordance with such member's usual practice or as required by any state or federal securities laws, or any rule or regulation thereunder.

(b) As used in paragraph (a) of this Rule, the term "customer" means any person who, in the regular course of such member's business, has cash or securities in the possession of such member.