26 CFR 301.6226(b)-1: (b)-1 5-percent group.

(a) In general. All members of a 5-percent group shall join in filing any petition for judicial review. The designation of a partner as a representative of a notice group does not authorize that partner to file a petition for a readjustment of partnership items on behalf of the notice group.

(b) Effective date. This section is applicable to partnership taxable years beginning on or after October 4, 2001. For years beginning prior to October 4, 2001, see § 301.6226(b)-1T contained in 26 CFR part 1, revised April 1, 2001.