Section 20.6694-3 - 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 estate tax under chapter 11 of subtitle B of the Internal Revenue Code (Code) shall be subject to penalties under section 6694(b) of the Code 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 78451 , Dec. 22, 2008