### Question
How is the "contribution base unit" defined?


### Answer
The term **contribution base unit** is defined in *26 U.S.C. § 418B* as follows -

> a unit with respect to which an employer has an obligation to contribute under a multiemployer plan (as defined in regulations prescribed by the Secretary)

#### Citation:
  - *26 U.S.C. § 418B*
  - Heading: **Subtitle A-Income Taxes > CHAPTER 1-NORMAL TAXES AND SURTAXES > Subchapter D-Deferred Compensation, Etc. > PART I-PENSION, PROFIT-SHARING, STOCK BONUS PLANS, ETC. > Subpart C-Special Rules for Multiemployer Plans**

