Methods for computing withdrawal liability

The amount of the unfunded vested benefits allocable to an employer that withdraws from a plan shall be determined in accordance with subsection (b), (c), or (d) of this section. Except as provided in subsections (c) and (d), the amount of unfunded vested benefits allocable to an employer that withdraws is the sum of— An employer’s proportional share of the unamortized amount of the change in the plan’s unfunded vested benefits for plan years ending after September 25, 1980, is the sum of the employer’s proportional shares of the unamortized amount of the change in unfunded vested benefits for each plan year in which the employer has an obligation to contribute under the plan ending— The change in a plan’s unfunded vested benefits for a plan year is the amount by which— the sum of— An employer’s proportional share of the unamortized amount of a change in unfunded vested benefits is the product of— a fraction— An employer’s proportional share of the unamortized amount of the plan’s unfunded vested benefits for the last plan year ending before September 26, 1980, is the product of— a fraction— the denominator of which is the sum of all contributions made for the most recent 5 plan years ending before September 26, 1980, by all employers— Except as otherwise provided in regulations prescribed by the corporation, the reallocated unfunded vested benefits for a plan year is the sum of— An employer’s proportional share of the unamortized amount of the reallocated unfunded vested benefits with respect to a plan year is the product of— The amount determined under this subparagraph is the product of— a fraction— The amount determined under this subparagraph is the product of— an amount equal to— a fraction— The amount of the unfunded vested benefits allocable to an employer under this paragraph is the product of— a fraction— The amount of the unfunded vested benefits allocable to an employer under this paragraph is equal to the sum of— The value of plan assets determined under this subparagraph is the value of plan assets allocated to nonforfeitable benefits which are attributable to service with the employers who have an obligation to contribute under the plan in the plan year preceding the plan year in which the employer withdraws, which is determined by multiplying— a fraction— The share of plan assets, determined under subparagraph (C), which is allocated to the employer shall be determined in accordance with one of the following methods which shall be adopted by the plan by amendment: by multiplying the value of plan assets determined under subparagraph (C) by a fraction— by multiplying the value of plan assets determined under subparagraph (C) by a fraction— by multiplying the value of plan assets under subparagraph (C) by a fraction— The amount of the plan’s unfunded vested benefits for a plan year preceding the plan year in which an employer withdraws, which is not attributable to service with employers who have an obligation to contribute under the plan in the plan year preceding the plan year in which such employer withdraws, is equal to— an amount equal to— an amount equal to— In the case of a transfer of liabilities to another plan incident to an employer’s withdrawal or partial withdrawal, the withdrawn employer’s liability under this part shall be reduced in an amount equal to the value, as of the end of the last plan year ending on or before the date of the withdrawal, of the transferred unfunded vested benefits. In the case of a withdrawal following a merger of multiemployer plans, subsection (b), (c), or (d) shall be applied in accordance with regulations prescribed by the corporation; except that, if a withdrawal occurs in the first plan year beginning after a merger of multiemployer plans, the determination under this section shall be made as if each of the multiemployer plans had remained separate plans.