26 U.S.C. § 6204
Section 6204 · Supplemental assessments
Amended 3 times on record
Applied in 19 court decisions — leading case United States v. Schroeder (1990)
Most recently applied in Johnston v. Comm'r (October 2004)
How often courts cite this section
Court decisions citing this, by year.Markers show enactment, consequential amendments, and circuit splits over this section — watch for a citation surge after a change or a disagreement. The dip in the last several years is a data-coverage gap, not a real trend — our corpus holds fewer opinions from the most recent years, so recent citations are undercounted.
The Secretary may, at any time within the period prescribed for assessment, make a supplemental assessment whenever it is ascertained that any assessment is imperfect or incomplete in any material respect.
For restrictions on assessment of deficiencies in income, estate, gift, and certain excise taxes, see section 6213.
Editorial notes U.S. Code · Office of the Law Revision Counsel
Amendments
1976—Subsec. (a). Pub. L. 94–455 struck out “or his delegate” after “Secretary”.
1974—Subsec. (b). Pub. L. 93–406 substituted “gift, and certain excise taxes” for “and gift taxes”.
Effective Date of 1974 Amendment
Amendment by Pub. L. 93–406 applicable, except as otherwise provided in section 1017(c) through (i) of Pub. L. 93–406, for plan years beginning after Sept. 2, 1974, and, in the case of plans in existence on Jan. 1, 1974, amendment by Pub. L. 93–406 applicable for plan years beginning after Dec. 31, 1975, see section 1017 of Pub. L. 93–406, set out as an Effective Date; Transitional Rules note under section 410 of this title.