(1) The corporate credit union shall be exempt from the regular reserve requirements of Article 11, but at the end of each dividend period and prior to paying a dividend, or at the option of the credit union, on a monthly basis if dividends are paid more frequently than monthly, sums shall be set aside in a corporate reserve in accordance with the following schedule:

(a) When the credit union’s corporate reserve and undivided earnings are less than four percent of assets at the end of the transfer period, the credit union shall set aside an amount equal to .0015 times the credit union’s average daily assets for the transfer period times the number of days in the transfer period, divided by three hundred and sixty-five.

(b) This reserve requirement may be changed from time to time by the board as it deems appropriate.

(2) Charges may be made to the corporate reserve for loan losses and for investment losses caused by factors other than trading losses or market fluctuations. Other charges to the corporate reserve may only be made with the prior approval of the commissioner.