If any part of the capital of a national bank, State member bank, or bank applying for membership in the Federal Reserve System consists of preferred stock, the determination of whether or not the capital of such bank is impaired and the amount of such impairment shall be based upon the par value of its stock even though the amount which the holders of such preferred stock shall be entitled to receive in the event of retirement or liquidation shall be in excess of the par value of such preferred stock. If any such bank or trust company shall have outstanding any capital notes or debentures of the type which the Reconstruction Finance Corporation is authorized to purchase pursuant to the provisions of section 51d of this title, the capital of such bank may be deemed to be unimpaired if the sound value of its assets is not less than its total liabilities, including capital stock, but excluding such capital notes or debentures and any obligations of the bank expressly subordinated thereto. Notwithstanding any other provision of law, the holders of preferred stock issued by a national banking association pursuant to the provisions of the Emergency Banking and Bank Conservation Act, approved March 9, 1933, as amended, shall be entitled to receive such cumulative dividends on the purchase price received by the association for such stock and, in the event of the retirement of such stock, to receive such retirement price, not in excess of such purchase price plus all accumulated dividends, as may be provided in the articles of association with the approval of the Comptroller of the Currency. If the association is placed in voluntary liquidation, or if a conservator or a receiver is appointed therefor, no payment shall be made to the holders of common stock until the holders of preferred stock shall have been paid in full such amount as may be provided in the articles of association with the approval of the Comptroller of the Currency, not in excess of such purchase price of such preferred stock plus all accumulated dividends.