For purposes of this section:
A plan is a "single plan" if and only if, on an ongoing basis, all of the plan assets are available to pay benefits to employees who are covered by the plan and their beneficiaries. For purposes of the preceding sentence, all the assets of a plan will not fail to be available to provide all the benefits of a plan merely because the plan is funded in part or in whole with allocated insurance instruments. A plan will not fail to be a single plan merely because of the following:
(i) The plan has several distinct benefit structures which apply either to the same or different participants,
(ii) The plan has several plan documents,
(iii) Several employers, whether or not affiliated, contribute to the plan,
(iv) The assets of the plan are invested in several trusts or annuity contracts, or
(v) Separate accounting is maintained for purposes of cost allocation but not for purposes of providing benefits under the plan.
However, more than one plan will exist if a portion of the plan assets is not available to pay some of the benefits. This will be so even if each plan has the same benefit structure or plan document, or if all or part of the assets are invested in one trust with separate accounting with respect to each plan.
The terms "merger" or "consolidation" means the combining of two or more plans into a single plan. A merger or consolidation will not occur merely because one or more corporations undergo a reorganization (whether or not taxable). Furthermore, a merger or consolidation will not occur if two plans are not combined into a single plan, such as by using one trust which limits the availability of assets of one plan to provide benefits to participants and beneficiaries of only that plan.