Page C3. In April lawmakers in the European Union (EU) approved a measure requiring EU nations to change their outside auditors every 10 years and limiting the other types of services that auditors can provide to their EU clients. Some of the largest banks and insurance companies in the U.S. could face difficulty complying with the measure since the new rules will apply to many European subsidiaries of U.S. multinationals, according to auditing experts. Companies such as J.P. Morgan Chase & Co. and American International Group Inc. will now have to decide whether to change auditors only for their European units or for the company as a whole. Changing the auditor for only some units could cause confusion since different firms would be auditing different units of the company, while changing the auditor of the entire company could be even more disruptive and force an American company to comply with European rules that are more restrictive than those in the U.S.