(a) Increasing board of directors. If authorized by the bank's articles of association, between shareholder meetings a majority of the board of directors may increase the number of the bank's directors within the limits specified in 12 U.S.C. 71a. The board of directors may increase the number of directors only by up to two directors, when the number of directors last elected by shareholders was 15 or fewer, and by up to four directors, when the number of directors last elected by shareholders was 16 or more.

(b) Vacancies. If a vacancy occurs on the board of directors, including a vacancy resulting from an increase in the number of directors, the vacancy may be filled by the shareholders, a majority of the board of directors remaining in office, or, if the directors remaining in office constitute fewer than a quorum, by an affirmative vote of a majority of all the directors remaining in office.