Knappe v. United States

Whether a taxpayer demonstrates "reasonable cause" under 26 U.S.C. § 6651(a)(1) or "ordinary business care and prudence" under 26 C.F.R. " 301.6651-1(c)(1) when, in reliance on the advice of the taxpayer"s accountant or attorney, the taxpayer files a tax return after the actual due date but within the time the accountant or attorney erroneously advised the taxpayer was available.