Per diem lowers your reported income, therefore loans based on income might be denied. Furthermore, on per diem, your SS retirement amount will be lesser. In realuty, per diem mostly benefits the companies for which one drives, not the employee. Some companies deduct from 1 CPM to several CPMs to allow drivers per diem. So, tge companies pay much less to you, to your SS retirement fund, and keep more for themselves. It is a sham for the driver, but a jackpot for companies. When has the RICH (companies) given to the poor (YOU) unless it means more $$$ for THEM?