The aggregate amount of a credit union's investments in the stock, capital notes and debentures of credit union organizations, together with the aggregate amount of loans to such organizations, shall not exceed three percent of the amount due to the members of the credit union on shares and deposits. For the purposes of this section, a loan shall include any loan or advance made directly or indirectly to a credit union organization (excluding accounts payable incurred in the ordinary course of business and paid within 60 days).