Notwithstanding any other provision of this Act, an amount paid or payable by a credit union to a member thereof in respect of a share of a class of the capital stock of the credit union (other than any such amount paid or payable as or on account of a reduction of the paid-up capital, redemption, acquisition or cancellation of the share by the credit union to the extent of the paid-up capital of the share) shall, where the share is not listed on a designated stock exchange, be deemed to have been paid or payable, as the case may be, by the credit union as interest and to have been received or to have been receivable, as the case may be, by the member as interest.