Except as provided in section 3304 of this title, a depository shall furnish and file with the Commissioner of Finance a corporate surety bond, satisfactory to the Commissioner, to secure governmental funds deposited with it. The Commissioner of Finance shall not approve any depository bond unless he is fully satisfied that the bond is in proper form, the securities sufficient, the depository is financially sound, and the capital stock claimed by it is fully paid up and not impaired.