Treas. Reg. § 1.414(r)-6

(a) In general. A separate line of business (as determined under § 1.414(r)-3) that does not satisfy any of the safe harbors in § 1.414(r)-5 for a testing year nonetheless satisfies the administrative scrutiny requirement of § 1.414(r)-1(b)(2)(iv)(D) if the employer requests and receives from the Commissioner an individual determination under this section that the separate line of business satisfies the requirement of administrative scrutiny for the testing year. This section implements the individual determinations provided for under section 414(r)(2)(C). The Commissioner shall issue such an individual determination only when it is consistent with the purpose of section 414(r), taking into account the nondiscrimination requirements of sections 401(a)(4) and 410(b). Paragraph (b) of this section authorizes the Commissioner to establish procedures for requesting and granting individual determinations.

(b) Authority to establish procedures. The Commissioner may, in revenue rulings and procedures, notices, and other guidance, published in the Internal Revenue Bulletin (see § 601.601(d)(2)(ii)(b) of this chapter), provide any additional guidance that may be necessary or appropriate for requesting and granting individual determinations under this section. For example, such guidance may specify the circumstances in which an employer may request an individual determination and factors to be taken into account in deciding whether to grant a favorable individual determination. In addition, such guidance may describe situations that automatically fail the administrative scrutiny requirement.