Rev. Proc. 2019-48, 2019-51 I.R.B.

1392 (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. 2019-48 (or successor). Notice 2021-52, 2021-38 I.R.B. 381, provides the rates and list of high-cost localities for the period October 1, 2021, to September 30, 2022.