(a) Contingent assets represent a possible source of value to the utility contingent upon the fulfillment of conditions regarded as uncertain. Contingent liabilities include items which may under certain conditions become obligations of the utility but which are neither direct nor assumed liabilities at the date of the balance sheet. In the annual report to the commission, contingent assets and contingent liabilities shall not be included in the balance sheet but shall be shown in a supplementary statement accompanying it.