plan administrator or other responsible party (including a plan service provider or trustee or issuer of an individual retirement plan receiving a transfer described in section 401(a)(31)(B)) has— (A) satisfied the requirements of section 6057(a) of the Internal Revenue Code of 1986, (B) made at least one unsuccessful attempt to contact the individual at the most recent address maintained for the individual in the records of the plan, by certified mail or other similar delivery service if the most recent address is a physical address, and by electronic mail or other electronic communication if the only address on record is an electronic address, and (C) has taken at least one (two, in the case of an individual for whom the plan records contain only an electronic address) of the additional measures described in paragraph (3) to attempt to locate the individual. (3) Additional measures The additional measures described in this paragraph are the following, when taken by a plan administrator or other responsible party: (A) Checked with the administrator of a related plan or checked the plan sponsor’s records for an updated address. (B) Made at least one unsuccessful attempt to contact the individual’s designated plan beneficiary, by the methods described in paragraph (2)(B). (C) Performed at least one search using free electronic search tools. (D) Attempted to locate the participant using a commercial locator service. (4) Cessation of status An individual shall cease to be treated as a lost or missing participant during any period the plan administrator has actual knowledge of the individual’s whereabouts and how to contact the individual, except that the requirements described in paragraph (1) shall be waived for the 180-day period beginning on the date the plan administrator first had such actual knowledge. (5) Joint regulatory authority Any temporary, proposed, or final regulation or other guidance of general applicability under this subsection shall be issued jointly by the Internal Revenue Service, Department