[Code of Federal Regulations]
[Title 26, Volume 13]
[Revised as of April 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 26CFR]

[Page 472]
 
                       TITLE 26--INTERNAL REVENUE
 
    CHAPTER I--INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY 
                               (CONTINUED)
 
Procedure and Administration--Table of Contents
 
Sec.  1.6661-1  Addition to tax in the case of a substantial 
understatement of tax liability.

    (a) In general. Section 6661 imposes an addition to tax (penalty) 
for an understatement of tax liability that constitutes a substantial 
understatement of income tax. This section prescribes the effective date 
of the penalty. The manner of computing understatements subject to the 
penalty is set forth in Sec.  1.6661-2. The definition of ``substantial 
authority'' is set forth in Sec.  1.6661-3. Rules concerning the 
adequacy of disclosure are set forth in Sec.  1.6661-4. The treatment of 
``tax shelters'' is provided in Sec.  1.6661-5. The circumstances in 
which the penalty may or will be waived by the Commissioner are set 
forth in Sec.  1.6661-6.
    (b) Effective date. The penalty under section 6661 applies to 
returns the due date (determined without regard to extensions of the 
time for filing) of which is after December 31, 1982. The penalty does 
not apply to amended returns, so-called, if the due date for the return 
to which the amended return relates (determined without regard to 
extensions) is before January 1, 1983.

[T.D. 8017, 50 FR 12014, Mar. 27, 1985]