---
kind: "section"
citation: "29 U.S.C. § 1386"
title: "29"
title_heading: "Labor"
number: "1386"
heading: "Adjustment for partial withdrawal; determination of amount; reduction for partial withdrawal liability; procedures applicable"
release: "119-102"
date: "2026-07-12"
url: "https://uscodex.org/usc/29/1386"
units:
  - "Chapter 18 — Employee Retirement Income Security Program"
  - "Subchapter III — Plan Termination Insurance"
  - "Subtitle E — Special Provisions for Multiemployer Plans"
  - "Part 1 — employer withdrawals"
---

# §1386. Adjustment for partial withdrawal; determination of amount; reduction for partial withdrawal liability; procedures applicable

- (a) The amount of an employer’s liability for a [partial withdrawal](/usc/29/1381.md?p=b-3), before the application of sections [1399(c)(1)](/usc/29/1399.md?p=c-1) and [1405](/usc/29/1405.md) of this title, is equal to the product of—
  - (1) the amount determined under [section 1391 of this title](/usc/29/1391.md), and adjusted under [section 1389 of this title](/usc/29/1389.md) if appropriate, determined as if the employer had withdrawn from the plan in a [complete withdrawal](/usc/29/1381.md?p=b-2)—
    - (A) on the date of the [partial withdrawal](/usc/29/1381.md?p=b-3), or
    - (B) in the case of a [partial withdrawal](/usc/29/1381.md?p=b-3) described in [section 1385(a)(1) of this title](/usc/29/1385.md?p=a-1) (relating to 70-percent contribution decline), on the last day of the first plan year in the 3-year testing period,

    multiplied by

  - (2) a fraction which is 1 minus a fraction—
    - (A) the numerator of which is the employer’s [contribution base units](/usc/29/1301.md?p=a-11) for the plan year following the plan year in which the [partial withdrawal](/usc/29/1381.md?p=b-3) occurs, and
    - (B) the denominator of which is the average of the employer’s [contribution base units](/usc/29/1301.md?p=a-11) for—
      - (i) except as provided in [clause (ii)](#a-2-B-ii), the 5 plan years immediately preceding the plan year in which the [partial withdrawal](/usc/29/1381.md?p=b-3) occurs, or
      - (ii) in the case of a [partial withdrawal](/usc/29/1381.md?p=b-3) described in [section 1385(a)(1) of this title](/usc/29/1385.md?p=a-1) (relating to 70-percent contribution decline), the 5 plan years immediately preceding the beginning of the 3-year testing period.
- (b)
  - (1) In the case of an employer that has withdrawal liability for a [partial withdrawal](/usc/29/1381.md?p=b-3) from a plan, any withdrawal liability of that employer for a partial or [complete withdrawal](/usc/29/1381.md?p=b-2) from that plan in a subsequent plan year shall be reduced by the amount of any [partial withdrawal](/usc/29/1381.md?p=b-3) liability (reduced by any abatement or reduction of such liability) of the employer with respect to the plan for a previous plan year.
  - (2) The corporation shall prescribe such regulations as may be necessary to provide for proper adjustments in the reduction provided by [paragraph (1)](#b-1) for—
    - (A) changes in unfunded vested benefits arising after the close of the prior year for which [partial withdrawal](/usc/29/1381.md?p=b-3) liability was determined,
    - (B) changes in [contribution base units](/usc/29/1301.md?p=a-11) occurring after the close of the prior year for which [partial withdrawal](/usc/29/1381.md?p=b-3) liability was determined, and
    - (C) any other factors for which it determines adjustment to be appropriate,

    so that the liability for any complete or [partial withdrawal](/usc/29/1381.md?p=b-3) in any subsequent year (after the application of the reduction) properly reflects the employer’s share of liability with respect to the plan.


## Source credit

(Pub. L. 93–406, title IV, § 4206, as added Pub. L. 96–364, title I, § 104(2), Sept. 26, 1980, 94 Stat. 1222.)