Home › CFR › Title 26 › Part 40 › §40.6101-126 CFR §40.6101-1 — -1 Period covered by returns.Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗Copy linkSee § 40.6011(a)-1(a)(2) for the rules relating to the period covered by the return.