A vendor is telling us that we are not allowed to mail 1099s, specifically 1099MISC, to post office boxes. Per the IRS Helpline you should follow the instructions for each form. None of the instructions specify the address (street or PO)to be used but the form itself only refers to street address in the address section. Has anyone else heard this is prohibited and can you provide a citing for it? Thanks.

I would ask the vendor to provide the citation.