Per diem allowance

When are per diem payments taxable?
Payments will be taxable to the employee when any of these situations are true:
· No expense report is filed with the employer,
· The expense report filed does not include the date, time, place, amount and business purpose of the expense,
· A flat amount is given to the employee and no expense report is required, or
· Per diem is paid in excess of the allowable standard federal rate.
These per diem payments listed above would be treated as wages and employment taxes are due from the
employer

For more Info then go to following LInk:

https://www.irs.gov/pub/irs-regs/perdiemfaq%26a.prn.pdf