(1) In general. Except as provided in paragraph (a)(2) of this section, a subpart B plan must, within the time frame described in paragraph (b) of this section, have diligently searched for each distributee of the plan whose location the plan does not know with reasonable certainty upon close-out in accordance with regulations and other applicable guidance issued by the Secretary of Labor under section 404 of ERISA.

(2) Notifying plans. For a notifying plan, the requirement of paragraph (a)(1) of this section applies only to distributees identified in the filing with PBGC.