29 CFR §4050.203

1. (a)Options. A subpart B plan that is closing out upon plan termination may (but need not) elect, by filing under § 4050.205, that the subpart B plan—
   1. (1)Will be a “transferring plan,” that is, will pay a benefit transfer amount to PBGC for each distributee who is missing upon close-out of the plan and will be bound by the provisions of this subpart B to the extent that they apply to transferring plans, or
   2. (2)Will be a “notifying plan,” that is, will notify PBGC of the disposition of the benefits of each distributee identified in the filing who is missing upon close-out of the plan and will, with respect to those distributees, be bound by the provisions of this subpart B to the extent that they apply to notifying plans.
2. (b)Diligent search—(1) In general. Except as provided in paragraph (b)(2) of this section, for each distributee whose location the plan does not know with reasonable certainty upon close-out of a subpart B plan, the plan must have conducted a diligent search as described in § 4050.204.
   1. (2)Notifying plans. For a notifying plan, the requirement of paragraph (b)(1) of this section applies only to distributees identified in the filing with PBGC.
3. (c)Filing with PBGC—(1) In general. Except as provided in paragraph (c)(2) of this section, for each distributee who is missing upon close-out of a subpart B plan, the plan must file with PBGC as described in § 4050.205.
   1. (2)Notifying plans. For a notifying plan, the requirement of paragraph (c)(1) of this section applies only to distributees identified in the filing with PBGC.