- 18 - including negligence or disregard of rules or regulations and a substantial understatement of income tax. See sec. 6662(b)(1) and (2). “Negligence” includes any failure to make a reasonable attempt to comply with the provisions of the Internal Revenue Code, including any failure to keep adequate books and records or to substantiate items properly. See sec. 6662(c); sec. 1.6662-3(b)(1), Income Tax Regs. A “substantial understatement” includes an understatement of tax that exceeds the greater of 10 percent of the tax required to be shown on the return or $5,000. See sec. 6662(d)(1)(A); sec. 1.6662-4(b), Income Tax Regs. Section 6664(c)(1) provides that the penalty under section 6662(a) shall not apply to any portion of an underpayment if it is shown that there was reasonable cause for the taxpayer’s position and that the taxpayer acted in good faith with respect to that portion. The determination of whether a taxpayer acted with reasonable cause and in good faith is made on a case-by-case basis, taking into account all the pertinent facts and circumstances. Sec. 1.6664-4(b)(1), Income Tax Regs. The most important factor is the extent of the taxpayer’s effort to assess his proper tax liability for the year. Id. Petitioners had a substantial understatement of tax for 2002 since the understatement amount exceeded the greater of 10 percent of the tax required to be shown on the return or $5,000. Petitioners claimed deductions for 2003 farm expenses to whichPage: Previous 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 NextLast modified: March 27, 2008