26 CFR §20.6694-3

(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.