(a) General rule. If an employer is treated as operating qualified separate lines of business for purposes of
section 401(a)(26) in accordance with
§ 1.414(r)-1(b) for a testing year, the requirements of
section 401(a)(26) must be applied separately with respect to the employees of each qualified separate line of business for purposes of testing all plans of the employer for plan years that begin in the testing year (other than a plan tested under the special rule for employer-wide plans in
§ 1.414(r)-1(c)(3)(ii) for such a plan year). Conversely, if an employer is not treated as operating qualified separate lines of business for purposes of
section 401(a)(26) in accordance with
§ 1.414(r)-1(b) for a testing year, the requirements of
section 401(a)(26) must be applied on an employer-wide basis for purposes of testing all plans of the employer for plan years that begin in the testing years. See
§ 1414(r)-1(c)(3) and (d)(6). Paragraph (b) of this section explains how the requirements of
section 401(a)(26) are applied separately with respect to the employees of a qualified separate line of business for purposes of testing a plan. Paragraph (c) of this section provides certain supplementary rules necessary for the application of this section.