I used to have a pretty good handle on per diem tax laws pre-TCJA, but I've been off on leave for several years and now that I back on an international category, I am noticing that a chunk of my per diem payments are listed as taxable. I tried reading through Pub 463, and now I'm more confused than before. It appears our setup is a Nonaccountable plan, which further down says:
Your employer will combine the amount of any reimbursement or other expense allowance paid to you under a nonaccountable plan with your wages, salary, or other pay. Your employer will report the total in box 1 of your Form W-2
It used to be that it wasn't included in Box 1 but was listed in box 12 with code L. The way I read this, it means that ALL of our per diem is taxable, and there's not exception. The fact that on my paycheck some is taxable and some non-taxable means that there's some basis for it not ALL being taxable; what is it? I can't find a source.