26 C.F.R. § 28.6694-3
Penalty for understatement due to willful, reckless, or intentional conduct
(a) In general. A person who is a tax return preparer of any return or claim for refund of any section 2801 tax is subject to penalties under section 6694(b) of the Code in the manner stated in § 1.6694-3 of this chapter.
(b) Applicability date. This section applies to returns and claims for refund filed, and advice provided, on or after January 14, 2025.