26 CFR § 41.6694-3
Penalty for understatement due to willful, reckless, or intentional conduct
June 25, 2020
(a) In general. A person who is a tax return preparer of any return or claim for refund of excise tax under section 4481 shall be subject to penalties under section 6694(b) in the manner stated in §1.6694-3 of this chapter.
(b) Effective/applicability date. This section is applicable to returns and claims for refund filed, and advice provided, after December 31, 2008.
[T.D. 9436, 73 FR 78456, Dec. 22, 2008]