(a) In general. A court decision with respect to a partner's income tax liability attributable to nonpartnership items shall not be a bar to further proceedings with respect to that partner's income tax liability if that partner's partnership items become nonpartnership items after the appropriate time to include such nonpartnership items in the earlier court proceeding has passed. Thus, the Internal Revenue Service could issue a later deficiency notice for the same taxable year with respect to that partner or that partner could bring a refund suit with respect to those items that have become nonpartnership items.

(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 § 301.6231(e)-2T contained in 26 CFR part 1, revised April 1, 2001.