If a policy dividend is hereafter declared or a reduction in rate is hereafter made or continued for the first or any subsequent year of insurance under any policy of group life insurance heretofore or hereafter issued to any policyholder, the excess, if any, of the aggregate dividends or rate reductions under such policy and all other group insurance policies of the policyholder over the aggregate expenditure for insurance under such policies made from funds contributed by the policyholder, or by an employer of insured persons, or by a union or association to which the insured persons belong, including expenditures made in connection with administration of such policies shall be applied by the policyholder for the sole benefit of insured employees or members.