SECTION 2. BACKGROUND

Rev. Proc. 2011–47, 2011–42 I.R.B. 520 (or successor), provides rules for using a per diem rate to substantiate, under § 274(d) of the Internal Revenue Code

and § 1.274–5 of the Income Tax Regulations, the amount of ordinary and necessary business expenses paid or incurred while traveling away from home. Taxpayers using the rates and list of high-cost localities provided in this notice must comply with Rev. Proc. 2011–47 (or successor). Notice 2017–54, 2017–42 I.R.B. 321, provides the rates and list of highcost localities for the period October 1, 2017, to September 30, 2018. Section 3.02(3) of Rev. Proc. 2011–47 (or successor) provides that the term “incidental expenses” has the same meaning as in the Federal Travel Regulations, 41 C.F.R. 300–3.1, and that future changes to the definition of incidental expenses in the Federal Travel Regulations would be announced in the annual per diem notice. Subsequent to the publication of Rev. Proc. 2011–47, the General Services Administration published final regulations revising the definition of incidental expenses under the Federal Travel Regulations to include only fees and tips given to porters, baggage carriers, hotel staff, and staff on ships. Transportation between places of lodging or business and places where meals are taken, and the mailing cost of filing travel vouchers and paying employer-sponsored charge card billings, are no longer included in incidental expenses. Accordingly, taxpayers using the per diem rates may separately deduct, if permitted, or be reimbursed for transportation and mailing expenses.