(a) Waiver of liability for a 70-percent contribution decline. An employer that has incurred a partial withdrawal under section 4205(a)(1) of ERISA shall have no obligation to make payments with respect to that partial withdrawal (other than delinquent payments) for plan years beginning after the second consecutive plan year in which the conditions of either paragraph (a)(1) or (a)(2) are satisfied for each of the two years:

(1) The number of contribution base units with respect to which the employer has an obligation to contribute under the plan for each year is not less than 90 percent of the total number of contribution base units with respect to which the employer had an obligation to contribute to the plan for the high base year (as defined in paragraph (d) of this section).

(2) The conditions of this paragraph are satisfied if—

(i) The number of contribution base units with respect to which the employer has an obligation to contribute for each year exceeds 30 percent of the total number of contribution base units with respect to which the employer had an obligation to contribute to the plan for the high base year (as defined in paragraph (d) of this section); and

(ii) The total number of contribution base units with respect to which all employers under the plan have obligations to contribute in each of the two years is not less than 90 percent of the total number of contribution base units for which all employers had obligations to contribute in the partial withdrawal year.

(b) Waiver of liability for a partial cessation of the employer's contribution obligation. Except as provided in § 4208.8, an employer that has incurred partial withdrawal liability under section 4205(a)(2) of ERISA shall have no obligation to make payments with respect to that partial withdrawal (other than delinquent payments) for plan years beginning after the second consecutive plan year in which the employer satisfies the conditions under either paragraph (b)(1) or (b)(2) of this section.

(1) Partial restoration of withdrawn work. The employer satisfies the conditions under this paragraph if, for each of two consecutive plan years—

(i) The employer makes contributions for the same facility or under the same collective bargaining agreement that gave rise to the partial withdrawal;

(ii) The employer's contribution base units for that facility or under that agreement exceed 30 percent of the contribution base units with respect to which the employer had an obligation to contribute for that facility or under that agreement for the high base year (as defined in paragraph (d) of this section); and

(iii) The total number of contribution base units with respect to which the employer has an obligation to contribute to the plan equals at least 90 percent of the total number of contribution base units with respect to which the employer had an obligation to contribute under the plan for the high base year (as defined in paragraph (d) of this section).

(2) Substantial restoration of withdrawn work. The employer satisfies the conditions under this paragraph if, for each of two consecutive plan years—

(i) The employer makes contributions for the same facility or under the same collective bargaining agreement that gave rise to the partial withdrawal;

(ii) The employer's contribution base units for that facility or under that agreement are not less than 90 percent of the contribution base units with respect to which the employer had an obligation to contribute for that facility or under that agreement for the high base year (as defined in paragraph (d) of this section); and

(iii) The total number of contribution base units with respect to which the employer has an obligation to contribute to the plan equals or exceeds the sum of—

(A) The number of contribution base units with respect to which the employer had an obligation to contribute in the year prior to the partial withdrawal year, determined without regard to the contribution base units for the facility or under the agreement that gave rise to the partial withdrawal; and

(B) 90 percent of the contribution base units with respect to which the employer had an obligation to contribute for that facility or under that agreement in either the year prior to the partial withdrawal year or the high base year (as defined in paragraph (d) of this section), whichever is less.

(c) Reduction in annual partial withdrawal liability payment—(1) Partial withdrawals under section 4205(a)(1). An employer shall be entitled to a reduction of its annual partial withdrawal liability payment for a plan year if the number of contribution base units with respect to which the employer had an obligation to contribute during the plan year exceeds the greater of—

(i) 110 percent (or such lower number as the plan may, by amendment, adopt) of the number of contribution base units with respect to which the employer had an obligation to contribute in the partial withdrawal year; or

(ii) The total number of contribution base units with respect to which the employer had an obligation to contribute to the plan for the plan year following the partial withdrawal year.

(2) Partial withdrawals under section 4205(a)(2). An employer that resumes the obligation to contribute with respect to a facility or collective bargaining agreement that gave rise to a partial withdrawal, but does not qualify to have that liability waived under paragraph (b) of this section, shall have its annual partial withdrawal liability payment reduced for any plan year in which the total number of contribution base units with respect to which the employer has an obligation to contribute equals or exceeds the sum of—

(i) The number of contribution base units for the reentered facility or agreement during that year; and

(ii) The total number of contribution base units with respect to which the employer had an obligation to contribute to the plan for the year following the partial withdrawal year.

(d) High base year. For purposes of paragraphs (a) and (b)(1)(iii) of this section, the high base year contributions are the average of the total contribution base units for the two plan years for which the employer's total contribution base units were highest within the five plan years immediately preceding the beginning of the 3-year testing period defined in section 4205(b)(1)(B)(i) of ERISA, with respect to paragraph (a) of this section, or the partial withdrawal year, with respect to paragraph (b)(1)(iii) of this section. For purposes of paragraphs (b)(1)(ii) and (b)(2) of this section, the high base year contributions are the average number of contribution base units for the facility or under the agreement for the two plan years for which the employer's contribution base units for that facility or under that agreement were highest within the five plan years immediately preceding the partial withdrawal.