- 28 - Commissioner with respect to a factual issue affecting the taxpayer’s liability for tax where the taxpayer introduces credible evidence with respect to such a factual issue and meets certain substantiation requirements set forth in section 7491(a)(2)(A) and (B). Respondent contends that petitioners’ argument as to the burden of proof was untimely raised and that, even if it had been timely, it is petitioners’ burden to show that they have met the requirements of section 7491(a)(2), which they have not done. We agree with respondent that petitioners’ attempt to raise section 7491 for the first time in their posttrial brief is untimely. Under section 7491 petitioners must, for example, show that they cooperated during the audit and that they met substantiation requirements. Petitioners’ attempt on brief to show that they met the requirements by the simple expediency of stating that respondent did not question the substantiation or that they cooperated will not suffice. Petitioners, by raising those allegations on brief, do not afford respondent the opportunity to test the allegations by cross-examination or by producing evidence to show otherwise. Therefore, we hold that petitioners’ attempt to shift the burden under section 7491 causes prejudicePage: Previous 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 NextLast modified: March 27, 2008