(3) Definitions.

1. (i) For purposes of this section, the term “multiple employer plan” shall mean a multiemployer plan as defined in section 3(37) of the Act and section 414(f) of the Code or a multiple employer plan within the meaning of sections 413 (b) and (c) of the Code and the regulations issued thereunder. Notwithstanding the preceding sentence, a plan maintained solely by members of the same controlled group of corporations within the meaning of paragraph (d) of this section or by trades or businesses which are under the common control of one person or group of persons within the meaning of paragraph (e) of this section shall not be deemed to be a multiple employer plan for purposes of this section, and such plan is required to apply the rules under this section which are applicable to controlled groups of corporations or commonly controlled trades or businesses respectively.
2. (ii) For purposes of this section, the term “covered service” shall mean service with an employer or employers maintaining the plan within a job classification or class of employees covered under the plan.
3. (iii) For purposes of this section the term “noncovered service” shall mean service with an employer or employers maintaining the plan which is not covered service.

4. (iv)

   1. (A) General. For purposes of this section noncovered service shall be deemed “contiguous” if (1) the noncovered service precedes or follows covered service and (2) no quit, discharge, or retirement occurs between such covered service and noncovered service.

   2. (B) Exception. Notwithstanding the preceding paragraph, in the case of a controlled group of corporations within the meaning of paragraph (d) of this section or trades or businesses which are under the common control of one person or group of persons within the meaning of paragraph (e) of this section, any transfer of an employee from one member of the controlled group to another member or from one trade or business under common control to another trade or business under the common control of the same person or group of persons shall result in the period of noncovered service which immediately precedes or follows such transfer being deemed “noncontiguous” for purposes of paragraph (c) of this section.

      Diagram No. 1. (Multiple Employer Plan.)

      

      Assume for purposes of diagram No. 1 that X and Y are both employers who are required to contribute to a multiple employer plan and that neither employer maintains any other plan. Covered service is represented by the shaded segments of the diagram. After completing 1 year of noncovered service, employee A immediately enters covered service with X and completes 4 years of covered service. For purposes of eligibility to participate and vesting, the plan is required to credit employee A with 5 years of service with employer X because his period of service with X includes a period of covered service and a period of contiguous noncovered service. On the other hand, employee B, immediately after completing 2 years of noncovered service with X, enters covered service with Y. Because B quit employment with X, his period of noncovered service with X is not contiguous and, therefore, is not required to be taken into account. In the case of employee C, the plan is required to take into account all service with employers X and Y because employee C is employed in covered service with both employers. Diagram No. 2. (Multiple Employer.) The multiple employer plan rules with respect to noncovered service are illustrated in diagram No. 2. Assume that X and Y are both employers who are required to contribute to a multiple employer plan and that neither employer maintains any other plan. Covered service is represented by the shaded segments of the diagram. Employee E completed 3 years of service with employer X in covered service and then immediately entered noncovered service with X. Because E's noncovered service is contiguous, the plan is required to take into account all service with X for purposes of eligibility to participate and vesting under the multiple employer plan. Employee F does not continue to receive credit; F quit the employment of Y and entered noncovered service with X.

   3. (d) Controlled groups of corporations.
   4. (1) With respect to a plan maintained by one or more members of a controlled group of corporations (within the meaning of section 1563(a) of the Code, determined without regard to sections 1563(a)(4) and (e)(3)(C), all employees of such corporations shall be treated as employed by a single employer.
   5. (2) Accordingly, except as referred to in paragraph (a)(1) and provided in paragraph (f) of this section, in determining an employee's service for eligibility to participate and vesting purposes, all service with any employer which is a member of the controlled group of corporations shall be taken into account. Except as referred to in paragraph (a)(2) and provided in paragraph (f) of this section, in determining a participant's service for benefit accrual purposes, all service during periods of participation covered under the plan with any employer which is a member of the controlled group of corporations shall be taken into account.

   6. (e) Commonly controlled trades or businesses. With respect to a plan maintained only by one or more trades or businesses (whether or not incorporated) which are under common control within the meaning of section 414(c) of the Code and the regulations issued thereunder, all employees of such trades or businesses shall be treated as employed by a single employer. Accordingly, except as referred to in paragraph (a)(1) and provided in paragraph (f) of this section, in determining an employee's service for eligibility to participate and vesting purposes, all service with any employer which is under common control shall be taken into account. Except as referred to in paragraph (a)(2) and provided in paragraph (f) of this section, in determining a participant's service for benefit accrual purposes, all service during periods of participation covered under the plan with any employer which is under common control shall be taken into account.

      Diagram No. 3. (Controlled group or commonly controlled trade or business.)

      

      Assume for purposes of diagram No. 3 that X and Y are either members of the same controlled group of corporations or trades or businesses which are under the same common control. The dotted segments of the diagram represent plan coverage under plans separately maintained by X and Y. Neither employer maintains any other plans. Because A1, B1, C1, and D1 have their service with X and Y treated as if X and Y were a single employer, the plans are required to take into account all service with X and Y for eligibility to participate and vesting purposes.

   7. (f) Special break in service rules.

      1. (1) In addition to service which may be disregarded under the statutory provisions referred to in paragraph (a) of this section, a multiple employer plan may disregard noncontiguous non- covered service.

      2. (2) In the case of a plan maintained solely by one or more members of a controlled group of corporations or one or more trades or businesses which are under common control, if one of the maintaining employers is also a participating employer in a multiple employer plan which includes other employers which are not members of the controlled group or commonly controlled trades or businesses, service with such other employer maintaining the multiple employer plan may be disregarded by the controlled group or commonly controlled plan.

         Diagram No. 4. (Break in Service Rules.)

         

         Diagram No. 4 illustrates the break in service rules of paragraph (f) of this section. Assume for purposes of diagram No. 4 that employer Z is controlled by employer X but employer Y's only relation to X and Z is that X, Y, and Z are required to contribute to a multiple employer plan. The multiple employer plan, represented by the shaded segments of the diagram, provides for 100 percent vesting after 10 years. X, Y, and Z maintain no other plans. Employee G completed 5 years of covered service with employer Y, and then moved to noncovered service with employer Z. G's noncovered service is noncontiguous (see employee F in diagram No. 2 above), and such service may be disregarded for purposes of the multiple employer plan under the rule in paragraph (f)(1). Employee H completed 2 years of covered service with employer Y and then entered covered service with employer X for 1 year. The multiple employer plan is required to credit H with 3 years of service. H then entered noncovered service with employer Z. H's noncovered service is noncontiguous (see employee F in diagram No. 2 above), and such service may be disregarded for purposes of the multiple employer plan under the rule in paragraph (f)(1).

   8. (g) Rule of parity. For purposes of sections 202(b)(4) and 203(b)(3)(D) of the Act and sections 410(a)(5)(D) and 411(a)(6)(D) of the Code, in the case of an employee who is a nonvested participant in employer-derived accrued benefits at the time he incurs a 1-year break in service, years of service completed by such employee before such break are not required to be taken into account if at such time he incurs consecutive 1-year breaks in service which equal or exceed the aggregate number of years of service before such breaks. This is so even though the period of noncontiguous noncovered service with an employer or employers maintaining the plan may subsequently be deemed contiguous as the result of the employee entering covered service with the same employer maintaining the plan and, consequently, such plan may be required to credit such service.

      Diagram No. 5. (Rule of parity)

      

      Assume for purposes of diagram No. 5 that X and Y are both employers who are required to contribute to a multiple employer plan which contains a provision applying the rule of parity. Covered service is represented by the shaded segments of the diagram. The plan has 100% vesting after 10 years. X and Y maintain no other plan. The multiple employer plan credited employee I with 4 years of service with X when he quit employment with X and entered noncovered service with Y. As a result of 4 years of noncontiguous noncovered service with Y, employee I incurred 4 consecutive 1-year breaks in service, so that the multiple employer plan may disregard his prior service (i.e., the 4 years of service with X). When employee I entered covered service with Y (as a “new employee”), his 4 years of noncontiguous service with Y became contiguous for purposes of the multiple employer plan. Consequently, after 1 year of covered service with Y, the plan is required to credit employee I with 5 years of service.

   9. (h) Example. Under section 203(b)(1)(C) of the Act and section 411(a)(4)(C) of the Code, service with an employer prior to such employer's adoption of the plan need not be taken into account. The following example demonstrates that this rule applies even if an employee is employed in contiguous noncovered service. The example is applicable to any plan subject to the rules of this section. However, for purposes of clarity, the example assumes that X and Y are required to contribute to a multiple employer plan.

      Assume that employee D completed 3 years of covered service with employer Y as of the date X adopts the plan. Immediately after X's adoption of the plan D left covered service with Y and D entered covered service with X. His prior covered service with Y is required to be counted, and D remains a participant. On the other hand, if D had entered service with X any time prior to X's adoption of the plan and subsequently was covered by the plan when X adopted it, his prior service with Y must also be counted, unless such service may be disregarded under the break in service rules because the period of service with X before X's adoption of the plan was equal to or greater than his prior service with Y. For example, if X adopted the plan three years after D began employment with X, and consequently after D had incurred 3 consecutive 1-year breaks in service, his prior service with Y could be disregarded. (i) Comprehensive diagram. (No. 6) Assume for purposes of diagram No. 6 that employer Z is controlled by employer X within the meaning of paragraph (d) but employer Y's only relation to X and Z is that X, Y and Z are required to contribute to a multiple employer plan. The shaded segments represent coverage under the multiple employer plan which contains a provision applying the rule of parity. The dotted segment represents a separate plan maintained by Z. Both plans have 100% vesting after 10 years. Employee J completed 3 years of service with employer X in covered service with the multiple employer plan. J then entered non- covered service with Y and remained with Y for 1 year, and thereby incurred a 1-year break in service under the multiple employer plan. J then entered covered service with employer Y, thereby causing the noncovered service with Y to become contiguous. Covered service with X and contiguous noncovered and covered service with Y must be taken into account for purposes of the multiple employer plan; accordingly, that plan is required to credit J with a total of 5 years of service. J then left service with Y and entered noncovered service (with respect to the multiple employer plan) with Z. J remained in noncovered service with Z (with respect to the multiple employer plan) for 5 years and thereby incurred 5 consecutive 1-year break in service for purposes of the multiple employer plan. Consequently, the prior service with X and Y may be disregarded for purposes of the multiple employer plan. J then entered covered service under the multiple employer plan with Z and completed 1 year of service. Because the 5 years of noncovered service with Z is contiguous with the 1 year of covered service, the multiple employer plan is now required to credit J with 6 years of service for purposes of eligibility to participate and vesting. For purposes of Z's controlled group plan (i.e., dotted segment), employee J is entitled to receive credit for 9 years of service. The 3 years of service with X, a member of the controlled group, may not be disregarded under the rule of parity because J incurred only 2 consecutive 1-year breaks in service while employed with Y. When J entered service with Z covered under Z's controlled group plan, the 3 years of service with X were still required to be credited by the controlled group plan. In addition, J must receive credit for the 5 years of service with Z covered under the controlled group plan. Finally, when J moved to service with Z covered under the multiple employer plan the controlled group plan was required to credit J with an additional year of service.