U.S. Code of Federal Regulations
Regulations most recently checked for updates: Mar 27, 2023
(a) General. In a plan that uses the presumptive allocation method described in section 4211(b) of ERISA, the credit shall equal the sum of the unamortized old liabilities determined under paragraph (b) of this section, multiplied by the fractions described or determined under paragraph (c) of this section. When an employer's prior partial withdrawal liability has been reduced or waived, this credit shall be adjusted in accordance with § 4206.8.
(b) Unamortized old liabilities. The amounts determined under this paragraph are the employer's proportional shares, if any, of the unamortized amounts as of the end of the plan year preceding the withdrawal for which the credit is being calculated, of -
(1) The plan's unfunded vested benefits as of the end of the last plan year ending before September 26, 1980;
(2) The annual changes in the plan's unfunded vested benefits for plan years ending after September 25, 1980, and before the year of the prior partial withdrawal; and
(3) The reallocated unfunded vested benefits (if any), as determined under section 4211(b)(4) of ERISA, for plan years ending before the year of the prior partial withdrawal.
(c) Employer's allocable share of old liabilities. The sum of the amounts determined under paragraph (b) are multiplied by the two fractions described in this paragraph in order to determine the amount of the old liabilities that was previously assessed against the employer.
(1) The first fraction is the fraction determined under section 4206(a)(2) of ERISA for the prior partial withdrawal.
(2) The second fraction is a fraction, the numerator of which is the amount of the liability assessed against the employer for the prior partial withdrawal, and the denominator of which is the product of -
(i) The amount of unfunded vested benefits allocable to the employer as if it had completely withdrawn as of the date of the prior partial withdrawal (determined without regard to any adjustments), multiplied by -
(ii) The fraction determined under section 4206(a)(2) of ERISA for the prior partial withdrawal.