CFR›Title 29›Subtitle B›Chapter XL›Part 4001 ContainsSections 4001.1–4001.3CorpusDaily eCFRDisplayed edition2026-04-15Last updated2026-04-15 PART 4001—TERMINOLOGY Sections 4001.1 § 4001.1 Purpose and scope. 4001.2 § 4001.2 Definitions. 4001.3 § 4001.3 Trades or businesses under common control; controlled groups. Authority29 U.S.C. 1301, 1302(b)(3).Source61 FR 34010, July 1, 1996, unless otherwise noted. Previous 4000 Part 4000—Filing, Issuance, Computation of Time, and Record Retention Next 4002 Part 4002—Bylaws of the Pension Benefit Guaranty Corporation