12 CFR § 209.5 - The share register.
(a) Electronic or written record. A member bank's holding of Reserve Bank capital stock shall be represented by one (or at the option of the Reserve Bank, more than one) notation on the Reserve Bank's books. Such books may be electronic or in writing. Upon any issue or cancellation of Reserve Bank capital stock, the Reserve Bank shall record the member bank's new share position in its books (or eliminate the bank's share position from its books, as the case may be).
(b) Certification. A Reserve Bank may certify on request as to the number of shares held by a member bank and purchased before March 28, 1942, or as to the purchase and cancellation dates and prices of shares cancelled, as the case may be.