The capital of any corporation having capital stock shall be an amount at least equal to the sum of the aggregate par value of all issued shares having par value, plus the aggregate amount of the purchase price received by the corporation for the issue of shares without par value, plus such amounts as, from time to time, by resolution of the board of directors, may be transferred thereto. The excess, if any, at any given time of the total net assets of the corporation over the amount so determined to be capital shall be surplus.