(2) Aggregation For purposes of this subsection— (A) Aggregation group (i) Required aggregation The term “aggregation group” means— (I) each plan of the employer in which a key employee is a participant, and (II) each other plan of the employer which enables any plan described in subclause (I) to meet the requirements of section 401(a)(4) or 410. (ii) Permissive aggregation The employer may treat any plan not required to be included in an aggregation group under clause (i) as being part of such group if such group would continue to meet the requirements of sections 401(a)(4) and 410 with such plan being taken into account. (B) Top-heavy group The term “top-heavy group” means any aggregation group if— (i) the sum (as of the determination date) of— (I) the present value of the cumulative accrued benefits for key employees under all defined benefit plans included in such group, and (II) the aggregate of the accounts of key employees under all defined contribution plans included in such group, (ii) exceeds 60 percent of a similar sum determined for all employees.
26 USC § 416(g)(2)
None identified. Default scope is assumed to be the entire title.