(a) In general. This section provides a definition of “plan.” First, this section sets forth a definition of plan within the meaning of section 401(a) or 403(a). Then certain mandatory disaggregation and permissive aggregation rules are applied. The result is the definition of plan that applies for purposes of sections 410(b) and 401(a)(4). Thus, in general, the term “plan” as used in this section initially refers to a plan described in section 414(l) and to an annuity plan described in section 403(a), and the term “plan” as used in other sections under these regulations means the plan determined after application of this section. Paragraph (b) of this section provides that each single plan under section 414(l) is treated as a single plan for purposes of section 410(b). Paragraph (c) of this section describes the rules for certain plans that must be treated as comprising two or more separate plans, each of which is a single plan subject to section 410(b). Paragraph (d) of this section provides a rule permitting an employer to aggregate certain separate plans to form a single plan for purposes of section 410(b). Paragraph (e) of this section provides rules for determining the testing group of plans taken into account in determining whether a plan satisfies the average benefit percentage test of §1.410(b)-5.

(b) Separate asset pools are separate plans. Each single plan within the meaning of section 414(l) is a separate plan for purposes of section 410(b). See §1.414(l)-1(b). For example, if only a portion of the assets under a defined benefit plan is available, on an ongoing basis, to provide the benefits of certain employees, and the remaining assets are available only in certain limited cases to provide such benefits (but are available in all cases for the benefit of other employees), there are two separate plans. Similarly, the defined contribution portion of a plan described in section 414(k) is a separate plan from the defined benefit portion of that same plan. A single plan under section 414(l) is a single plan for purposes of section 410(b), even though the plan comprises separate written documents and separate trusts, each of which receives a separate determination letter from the Internal Revenue Service. A defined contribution plan does not comprise separate plans merely because it includes more than one trust, or merely because it provides for separate accounts and permits employees to direct the investment of the amounts allocated to their accounts. Further, a plan does not comprise separate plans merely because assets are separately invested in individual insurance or annuity contracts for employees.

(c) Mandatory disaggregation of certain plans—(1) Section 401(k) and 401(m) plans. The portion of a plan that is a section 401(k) plan and the portion that is not a section 401(k) plan are treated as separate plans for purposes of section 410(b). Similarly, the portion of a plan that is a section 401(m) plan and the portion that is not a section 401(m) plan are treated as separate plans for purposes of section 410(b). Thus, a plan that consists of elective contributions under a section 401(k) plan, employee and matching contributions under a section 401(m) plan, and contributions other than elective, employee, or matching contributions is treated as three separate plans for purposes of section 410(b). In addition, the portion of a plan that consists of contributions described in §1.401(k)-2(a)(5) (i.e., contributions that fail to satisfy the allocation or compensation requirements applicable to elective contributions and are therefore required to be tested separately) and the portion of the plan that does not consist of such contributions are treated as separate plans for purposes of section 410(b). Similarly, the portion of a plan that consists of contributions described in §1.410(m)-1(b)(4)(ii) (i.e., matching contributions that fail to satisfy the allocation and other requirements applicable to matching contributions and are therefore required to be tested separately) and the portion of the plan that does not consist of such contributions are treated as separate plans for purposes of section 410(b).

(2) ESOPs and non-ESOPs. The portion of a plan that is an ESOP and the portion of the plan that is not an ESOP are treated as separate plans for purposes of section 410(b), except as otherwise permitted under §54.4975-11(e) of this Chapter.

(3) Plans benefiting otherwise excludable employees. If an employer applies section 410(b) separately to the portion of a plan that benefits only employees who satisfy age and service conditions under the plan that are lower than the greatest minimum age and service conditions permissible under section 410(a), the plan is treated as comprising separate plans, one benefiting the employees who have satisfied the lower minimum age and service conditions but not the greatest minimum age and service conditions permitted under section 410(a) and one benefiting employees who have satisfied the greatest minimum age and service conditions permitted under section 410(a). See §410(b)-6(b)(3)(ii) for rules about testing otherwise excludable employees.

(4) Plans benefiting certain disaggregation populations of employees—(i) In general—(A) Single plan must be treated as separate plans. If a plan (i.e., a single plan within the meaning of section 414(l)) benefits employees of more than one disaggregation population, the plan must be disaggregated and treated as separate plans, each separate plan consisting of the portion of the plan benefiting the employees of each disaggregation population. See paragraph (c)(4)(ii) of this section for the definition of disaggregation population.

(B) Benefit accruals or allocations attributable to current status. Except as otherwise provided in paragraph (c)(4)(i)(C) of this section, in applying the rule of paragraph (c)(4)(i)(A) of this section, the portion of the plan benefiting employees of a disaggregation population consists of all benefits accrued by, or all allocations made to, employees while they were members of the disaggregation population.

(C) Exceptions for certain benefit accruals—(1) Attribution of benefits to first disaggregation population. If employees benefiting under a plan change from one disaggregation population to a second disaggregation population, benefits they accrue while members of the second disaggregation population that are attributable to years of service previously credited while the employees were members of the first disaggregation population may be treated as provided to them in their status as members of the first disaggregation population and thus included in the portion of the plan benefiting employees of the first disaggregation population. This special treatment is available only if it is applied on a consistent basis, if it does not result in significant discrimination in favor of highly compensated employees, and if the plan provision providing the additional benefits applies on the same terms to all similarly-situated employees. For example, if all formerly collectively bargained employees accrue additional benefits under a plan after becoming noncollectively bargained employees, then those benefit increases may be treated as included in the portion of the plan benefiting collectively bargained employees if they are attributable to years of service credited while the employees were collectively bargained (e.g., where the additional benefits result from compensation increases that occur while the employees are noncollectively bargained or from plan amendments affecting benefits earned while collectively bargained that are adopted while the employees are noncollectively bargained) and if such treatment does not result in significant discrimination in favor of highly compensated employees.

(2) Attribution of benefits to current disaggregation population. If employees benefiting under a plan change from one disaggregation population to another disaggregation population, benefits they accrue while members of the first disaggregation population may be treated as provided to them in their current status and thus included in the portion of the plan benefiting employees of the disaggregation population of which they are currently members. This special treatment is available only if it is applied on a consistent basis and if it does not result in significant discrimination in favor of highly compensated employees.

(D) Change in disaggregation populations—(1) Reasonable treatment. If, in previous years, the configuration of a plan's disaggregation populations differed from their configuration for the current year, for purposes of the benefits accrued by, or allocations made to, an employee for those years, the employee's status as a member of a current disaggregation population for those years must be determined on a reasonable basis. A different configuration occurs, for example, if disaggregation populations exist for the first time, such as when an employer is first treated as operating qualified separate lines of business, or if the existing disaggregation populations change, such as when an employer redesignates its qualified separate lines of business.

(2) Example. The following example illustrates the application of this paragraph (c)(4)(i)(D).

(ii) Definition of disaggregation population—(A) Plan benefiting employees of qualified separate lines of business. If an employer is treated as operating qualified separate lines of business for purposes of section 410(b) in accordance with §1.414(r)-1(b), and a plan benefits employees of more than one qualified separate line of business, the employees of each qualified separate line of business are separate disaggregation populations. In this case, the portion of the plan benefiting the employees of each qualified separate line of business is treated as a separate plan maintained by that qualified separate line of business. However, employees of different qualified separate lines of business who are benefiting under a plan that is tested under the special rule for employer-wide plans in §1.414(r)-1(c)(2)(ii) for a plan year are not separate disaggregation populations merely because they are employees of different qualified separate lines of business.

(B) Plan benefiting collectively bargained employees. If a plan benefits both collectively bargained employees and noncollectively bargained employees, the collectively bargained employees are one disaggregation population and the noncollectively bargained employees are another disaggregation population. If the population of collectively bargained employees includes employees covered under different collective bargaining agreements, the population of employees covered under each collective bargaining agreement is also a separate disaggregation population.

(C) Plan maintained by more than one employer. If a plan benefits employees of more than one employer, the employees of each employer are separate disaggregation populations. In this case, the portion of the plan benefiting the employees of each employer is treated as a separate plan maintained by that employer, which must satisfy section 410(b) by reference only to that employer's employees. However, for purposes of this paragraph (c)(4)(ii)(C), if the plan of one employer (or, in the case of a plan maintained by more than one employer, the plan provisions applicable to the employees of one employer) treats compensation or service with another employer as compensation or service with the first employer, then the current accruals attributable to that compensation or service are treated as provided to an employee of the first employer under the plan of the first employer (or the portion of a plan maintained by more than one employer benefiting employees of the first employer), and the provisions of paragraph (c)(4)(i)(C) of this section do not apply to those accruals. Thus, for example, if Plan A maintained by Employer X imputes service or compensation for an employee of Employer Y, then Plan A is not treated as benefiting the employees of more than one employer merely because of this imputation.

(5) Additional rule for plans benefiting employees of more than one qualified separate line of business. If a plan benefiting employees of more than one qualified separate line of business satisfies the reasonable classification requirement of §1.410(b)-4(b) before the application of paragraph (c)(4) of this section, then any portion of the plan that is treated as a separate plan as a result of the application of paragraphs (c)(4)(i)(A) and (ii)(A) of this section is deemed to satisfy that requirement.

(d) Permissive aggregation for ratio percentage and nondiscriminatory classification tests—(1) In general. Except as provided in paragraphs (d)(2) and (d)(3) of this section, for purposes of applying the ratio percentage test of §1.410(b)-2(b)(2) or the nondiscriminatory classification test of §1.410(b)-4, an employer may designate two or more separate plans (determined after application of paragraph (b) of this section) as a single plan. If an employer treats two or more separate plans as a single plan under this paragraph, the plans must be treated as a single plan for all purposes under sections 401(a)(4) and 410(b).

(2) Rules of disaggregation. An employer may not aggregate portions of a plan that are disaggregated under the rules of paragraph (c) of this section. Similarly, an employer may not aggregate two or more separate plans that would be disaggregated under the rules of paragraph (c) of this section if they were portions of the same plan. In addition, an employer may not aggregate an ESOP with another ESOP, except as permitted under §54.4975-11(e) of this Chapter.

(3) Duplicative aggregation. A plan may not be combined with two or more plans to form more than one single plan. Thus, for example, an employer that maintains plans A, B, and C may not aggregate plans A and B and plans A and C to form two single plans. However, the employer may apply the permissive aggregation rules of this paragraph (d) to form any one (and only one) of the following combinations: plan ABC, plans AB and C, plans AC and B, or plans A and BC.

(4) Special rule for plans benefiting employees of a qualified separate line of business. For purposes of paragraph (d)(1) of this section, an employer that is treated as operating qualified separate lines of business for purposes of section 410(b) in accordance with §1.414(r)-1(b) is permitted to aggregate the portions of two or more plans that benefit employees of the same qualified separate line of business (regardless of whether the employer elects to aggregate the portions of the same plans that benefit employees of the other qualified separate lines of business of the employer), provided that none of the plans is tested under the special rule for employer-wide plans in §1.414(r)-1 (c)(2)(ii). Thus, the employer is permitted to apply paragraph (d)(1) of this section with respect to two or more separate plans determined after the application of paragraphs (b) and (c)(4) of this section, but may not aggregate a plan that is tested under the special rule for employer-wide plans in §1.414(r)-1(c)(2)(ii) for a plan year with any portion of a plan that does not rely on that special rule for the plan year. In all other respects, the provisions of this paragraph (d) regarding permissive aggregation apply, including (but not limited to) the disaggregation rules under paragraph (d)(2) of this section (including the mandatory disaggregation rule of paragraph (c)(4) of this section), and the prohibition on duplicative aggregation under paragraph (d)(3) of this section. This paragraph (d)(4) applies only in the case of an employer that is treated as operating qualified separate lines of business for purposes of section 410(b) in accordance with §1.414(r)-1(b). See §§l.414(r)-1(c)(2) and 1.414(r)-8 (separate application of section 410(b) to the employees of a qualified separate line of business).

(5) Same plan year requirement. Two or more plans may not be aggregated and treated as a single plan under this paragraph (d) unless they have the same plan year.

(e) Determination of plans in testing group for average benefit percentage test—(1) In general. For purposes of applying the average benefit percentage test of §1.410(b)-5 with respect to a plan, all plans in the testing group must be taken into account. For this purpose, the plans in the testing group are the plan being tested and all other plans of the employer that could be permissively aggregated with that plan under paragraph (d) of this section. Whether two or more plans could be permissively aggregated under paragraph (d) of this section is determined (i) without regard to the rule in paragraph (d)(4) of this section that portions of two or more plans benefiting employees of the same line of business may not be aggregated if any of the plans is tested under the special rule for employer-wide plans in §1.414(r)-1(c)(2)(ii), (ii) without regard to paragraph (d)(5) of this section, and (iii) by applying paragraph (d)(2) of this section without regard to paragraphs (c)(1) and (c)(2) of this section.

(2) Examples. The following example illustrates the rules of this paragraph (e).

(f) Section 403(b) plans. In determining whether a plan satisfies section 410(b), a plan subject to section 403(b)(12)(A)(i) is disregarded. However, in determining whether a plan subject to section 403(b)(12)(A)(i) satisfied section 410(b), plans that are not subject to section 403(b)(12)(A)(i) may be taken into account.

[T.D. 8363, 56 FR 47655, Sept. 19, 1991, as amended by T.D. 8376, 56 FR 63433, Dec. 4, 1991; T.D. 8363, 57 FR 10819, 10954, Mar. 31, 1992; T.D. 8487, 58 FR 46843, Sept. 3, 1993; T.D. 8548, 59 FR 32914, June 27, 1994; T.D. 9169, 69 FR 78153, Dec. 29, 2004]