(a) In general. For a plan that is not a significantly affected plan, or that is a significantly affected plan only because the merger or transfer involves a plan that has terminated by mass withdrawal under section 4041A(a)(2) of ERISA, the actuarial valuation requirement under section 4231(b)(4) of ERISA and § 4231.3(a)(2) is satisfied if an actuarial valuation has been performed for the plan based on the plan's assets and liabilities as of a date not more than three years before the date on which the notice of the merger or transfer is filed.

(b) Significantly affected plans. For a significantly affected plan, other than a plan that is a significantly affected plan only because the merger or transfer involves a plan that has terminated by mass withdrawal under section 4041A(a)(2) of ERISA, the actuarial valuation requirement under section 4231(b)(4) of ERISA and § 4231.3(a)(2) is satisfied only if an actuarial valuation has been performed for the plan based on the plan's assets and liabilities as of a date not earlier than the first day of the last plan year ending before the proposed effective date of the transaction. The valuation must separately identify assets, contributions, and liabilities being transferred and must be based on the actuarial assumptions and methods that are expected to be used for the plan for the first plan year beginning after the transfer.