26 CFR 301.6684-1: -1 Assessable penalties with respect to liability for tax under chapter 42.

(a) In general. If any person (as defined in section 7701(a)(1)) becomes liable for tax under any section of chapter 42 (other than section 4940 or 4948(a)), relating to private foundations, by reason of any act or failure to act which is not due to reasonable cause and either—

(1) Such person has theretofore (at any time) been liable for tax under any section of such chapter (other than section 4940 or 4948(a)), or

(2) Such act or failure to act is both willful and flagrant,

then such person shall be liable for a penalty equal to the amount of such tax.

(b) Showing of reasonable cause. The penalty imposed by section 6684 shall not apply to any person with respect to a violation of any section of chapter 42 if it is established to the satisfaction of the district director or director of the internal revenue service center that such violation was due to reasonable cause. An affirmative showing of reasonable cause must be made in the form of a written statement, containing a declaration by such person that it is made under the penalties of perjury, setting forth all the facts alleged as reasonable cause.

(c) Willful and flagrant. For purposes of this section, the term “willful and flagrant” has the same meaning as such term possesses in section 507(a)(2)(A) and the regulations thereunder.

(d) Effective date. This section shall take effect on January 1, 1970.