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SECTION 4. PER DIEM
Internal Revenue Bulletin 2001-42 · 2026-10-03 edition · updated 2026-10-04 · United States
SUBSTANTIATION METHOD
.01 Per diem allowance . If a payor pays a per diem allowance in lieu of reimbursing actual expenses for lodging, meal, and incidental expenses incurred or to be incurred by an employee for travel away
.03 Flat rate or stated schedule.
2001–42 I.R.B. 333 October 15, 2001
from home, the amount of the expenses that is deemed substantiated for each calendar day is equal to the lesser of the per diem allowance for such day or the amount computed at the federal per diem rate (see section 3.02 of this revenue procedure) for the locality of travel for such day (or partial day, see section 6.04 of this revenue procedure).
.02 Meals only per diem allowance . If a payor pays a per diem allowance only for meal and incidental expenses in lieu of reimbursing actual expenses for meal and incidental expenses incurred or to be incurred by an employee for travel away from home, the amount of the expenses that is deemed substantiated for each calendar day is equal to the lesser of the per diem allowance for such day or the amount computed at the federal M&IE rate (see section 3.02 of this revenue procedure) for the locality of travel for such day (or partial day, see section 6.04 of this revenue procedure). A per diem allowance is treated as paid only for meal and incidental expenses if (1) the payor pays the employee for actual expenses for lodging based on receipts submitted to the payor, (2) the payor provides the lodging in kind, (3) the payor pays the actual expenses for lodging directly to the provider of the lodging, (4) the payor does not have a reasonable belief that lodging expenses were or will be incurred by the employee, or (5) the allowance is computed on a basis similar to that used in computing the employee’s wages or other compensation ( e.g., the number of hours worked, miles traveled, or pieces produced).
.03 Optional method for meals only de- duction . In lieu of using actual expenses, employees and self-employed individuals, in computing the amount allowable as a deduction for ordinary and necessary meal and incidental expenses paid or incurred for travel away from home, may use an amount computed at the federal M&IE rate (see section 3.02 of this revenue procedure) for the locality of travel for each calendar day (or partial day, see section 6.04 of this revenue procedure) the employee or self-employed individual is away from home. Such amount will be deemed substantiated for purposes of paragraphs (b)(2) (travel away from home) and (c) of § 1.274–5, provided the employee or self-employed individual
substantiates the elements of time, place, and business purpose of the travel expenses in accordance with those regulations.
.04 Special rules for transportation in- dustry .
(1) In general . This section 4.04 applies to (a) a payor that pays a per diem allowance only for meal and incidental expenses for travel away from home as described in section 4.02 of this revenue procedure to an employee in the transportation industry, or (b) an employee or self-employed individual in the transportation industry who computes the amount allowable as a deduction for meal and incidental expenses for travel away from home in accordance with section 4.03 of this revenue procedure. (2) Rates . A taxpayer described in section 4.04(1) of this revenue procedure may treat $38 as the federal M&IE rate for any locality of travel in CONUS, and/or $42 as the federal M&IE rate for any locality of travel OCONUS. A payor that uses either (or both) of these special rates with respect to an employee must use the special rate(s) for all amounts subject to section 4.02 of this revenue procedure paid to that employee for travel away from home within CONUS and/or OCONUS, as the case may be, during the calendar year. Similarly, an employee or self-employed individual that uses either (or both) of these special rates must use the special rate(s) for all amounts computed pursuant to section 4.03 of this revenue procedure for travel away from home within CONUS and/or OCONUS, as the case may be, during the calendar year. See section 4.04(5) of this revenue procedure for transition rules.
(3) Periodic rule . A payor described in section 4.04(1) of this revenue procedure may compute the amount of the employee’s expenses that is deemed substantiated under section 4.02 of this revenue procedure periodically (not less frequently than monthly), rather than daily, by comparing the total per diem allowance paid for the period to the sum of the amounts computed at the federal M&IE rate(s) for the localities of travel for the days (or partial days, see section 6.04 of this revenue procedure) the employee is away from home during the period. For example, assume an employee in the transportation industry travels
away from home within CONUS on 17 days (including partial days, see section 6.04 of this revenue procedure) during a calendar month and receives a per diem allowance only for meal and incidental expenses from a payor that uses the special rule under section 4.04(2) of this revenue procedure. The amount deemed substantiated under section 4.02 of this revenue procedure is equal to the lesser of the total per diem allowance paid for the month or $646 (17 days at $38 per day).
(4) Transportation industry defined . For purposes of this section 4.04 of this revenue procedure, an employee or selfemployed individual is “in the transportation industry” only if the employee’s or individual’s work (a) is of the type that directly involves moving people or goods by airplane, barge, bus, ship, train, or truck, and (b) regularly requires travel away from home which, during any single trip away from home, usually involves travel to localities with differing federal M&IE rates. For purposes of the preceding sentence, a payor must determine that an employee or a group of employees is “in the transportation industry” by using a method that is consistently applied and in accordance with reasonable business practice.
(5) Transition rules . Under the calendar-year convention provided in section 4.04(2), a taxpayer who used the federal M&IE rates during the first 9 months of calendar year 2001 to substantiate the amount of an individual’s travel expenses under sections 4.02 or 4.03 of Rev. Proc. 2000–39 may not use, for that individual, the special transportation industry rates provided in this section 4.04 until January 1, 2002. Similarly, a taxpayer who used the special transportation industry rates during the first 9 months of calendar year 2001 to substantiate the amount of an individual’s travel expenses may not use, for that individual, the federal M&IE rates until January 1, 2002.
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