Any bank or trust company, with the written approval of the Commissioner and by majority vote of the outstanding voting stock, may by proper amendment to its certificate of incorporation authorize an increase in the common stock of the bank in the category of authorized but unissued stock. Such authorized but unissued stock may be issued from time to time to employees of the bank pursuant to a stock option or stock purchase plan adopted in accordance with the provisions of Section 40 of this act¹ or in exchange for convertible preferred stock or convertible capital debentures in accordance with the terms and provisions of such securities. Authorized but unissued stock may also be issued from time to time for such other purposes and considerations as may be approved by the board of directors of the bank and by the written approval of the Commissioner.