The timing of per diem payments is usually determined by individual company policy, but the "high-fidelity" business standard is either as an advance before travel begins or as a reimbursement after the trip is completed. If paid as an advance, the employee receives the funds to cover anticipated costs for meals and incidentals. If paid as a reimbursement, the employee typically must submit a "travel expense report" within 60 days of the trip. According to IRS guidelines, if the per diem rate paid is at or below the federal standard, it is non-taxable and doesn't require receipt tracking (though proof of the "business purpose" of the trip is still required). However, if the payment exceeds federal rates, the excess must be treated as taxable wages. In 2026, many digital-first companies use automated platforms that release per diem funds to a corporate card the moment a flight is booked, ensuring the traveler has liquid funds without needing to wait for a traditional payroll cycle.