SECTION 8. WITHHOLDING AND

PAYMENT OF EMPLOYMENT TAXES

.01 The portion of a per diem allowance, if any, that relates to the days of business travel substantiated and that exceeds the amount deemed substantiated for those days under section 4.01, 4.02, or 5 of this revenue procedure is treated as paid under a nonaccountable plan and is subject to withholding and payment of employment taxes. See § 1.62–2(h)(2)(i)(B).

.02 In the case of a per diem allowance paid as a reimbursement, the excess described in section 8.01 of this revenue procedure is subject to withholding and payment of employment taxes in the payroll period in which the payor reimburses the expenses for the days of travel substantiated. See § 1.62–2(h)(2)(i)(B)(2).

.03 In the case of a per diem allowance paid as an advance, the excess described in section 8.01 of this revenue procedure is subject to withholding and payment of employment taxes no later than the first payroll period following the payroll period in which the days of travel with respect to which the advance was paid are substantiated. See § 1.62–2(h)(2)(i)(B)(3). If some or all of the days of travel with respect to which the advance was paid are not substantiated within a reasonable period of time and the employee does not return the portion of the allowance that relates to those days within a reasonable period of time, the portion of the allowance that relates to those days is subject to withholding and payment of employment taxes no later than the first payroll period following the end of the reasonable period. See § 1.62–2(h)(2)(i)(A).

.04 In the case of a per diem allowance only for meal and incidental expenses for travel away from home paid to an employee in the transportation industry by a payor that uses the rule in section 4.04(4) of this revenue procedure, the excess of the per diem allowance paid for the period over the amount deemed substanti

ated for the period under section 4.02 of this revenue procedure (after applying section 4.04(4) of this revenue procedure), is subject to withholding and payment of employment taxes no later than the first payroll period following the payroll period in which the excess is computed. See § 1.62–2(h)(2)(i)(B)(4).

.05 For example, assume that an employer pays an employee a per diem allowance under an arrangement that otherwise meets the requirements of an accountable plan to cover business expenses for meals and lodging for travel away from home at a rate of 120 percent of the federal per diem rate for the localities to which the employee travels. The employer does not require the employee to return the 20 percent by which the reimbursement for those expenses exceeds the federal per diem rate. The employee substantiates 6 days of travel away from home: 2 days in a locality in which the federal per diem rate is $160 and 4 days in a locality in which the federal per diem rate is $120. The employer reimburses the employee $960 for the 6 days of travel away from home (2 x (120% x $160) + 4 x (120% x $120)), and does not require the employee to return the excess payment of $160 (2 days x $32 ($192-$160) + 4 days x $24 ($144-$120)). For the payroll period in which the employer reimburses the expenses, the employer must withhold and pay employment taxes on $160. See section 8.02 of this revenue procedure.

.06 If a per diem allowance arrangement has no mechanism or process to determine when an allowance exceeds the amount that may be deemed substantiated and the arrangement routinely pays allowances in excess of the amount that may be deemed substantiated without requiring actual substantiation of all the expenses or repayment of the excess amount, the failure of the arrangement to treat the excess allowances as wages for employment tax purposes causes all payments made under the arrangement to be treated as made under a nonaccountable plan. See Rev. Rul. 2006–56.