US Code
PART III— APPLICABLE RULES
§ 6665. Applicable rules

(a) Additions treated as taxExcept as otherwise provided in this title—(1) the additions to the tax, additional amounts, and penalties provided by this chapter shall be paid upon notice and demand and shall be assessed, collected, and paid in the same manner as taxes; and
(2) any reference in this title to “tax” imposed by this title shall be deemed also to refer to the additions to the tax, additional amounts, and penalties provided by this chapter.
(b) Procedure for assessing certain additions to taxFor purposes of subchapter B of chapter 63 (relating to deficiency procedures for income, estate, gift, and certain excise taxes), subsection (a) shall not apply to any addition to tax under section 6651, 6654, or 6655; except that it shall apply—(1) in the case of an addition described in section 6651, to that portion of such addition which is attributable to a deficiency in tax described in section 6211; or
(2) to an addition described in section 6654 or 6655, if no return is filed for the taxable year.