- 10 - an approximation. Vanicek v. Commissioner, 85 T.C. 731, 742-743 (1985). Without such a basis, any allowance would amount to unguided largesse. Williams v. United States, 245 F.2d 559, 560 (5th Cir. 1957). Certain business expenses may not be estimated because of the strict substantiation requirements of section 274(d). See sec. 280F(d)(4)(A); Sanford v. Commissioner, 50 T.C. 823, 827 (1968), affd. per curiam 412 F.2d 201 (2d Cir. 1969). For such expenses, only certain types of documentary evidence will suffice. Unreimbursed Employee Business Expenses Not Subject to Strict Substantiation We first consider the unreimbursed employee business expenses not subject to the strict substantiation requirements. We then examine those employee business expenses that are subject to the additional strict substantiation requirements. Business Use of the Home Petitioners claimed $4,190 miscellaneous expenses for business use of their home during 2003. Expenses for business use of a taxpayer’s home are deductible only under very limited circumstances. The taxpayer must show that the portion of the home purported to be used for business was exclusively used on aPage: Previous 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 NextLast modified: November 10, 2007