Section 157.6694-2 - Penalties for understatement due to an unreasonable position(a)In general. A person who is a tax return preparer of any return or claim for refund of tax under section 5891 of the Internal Revenue Code (Code) shall be subject to penalties under section 6694(a) of the Code in the manner stated in § 1.6694-2 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 78462 , Dec. 22, 2008