This is a state tax question.
My client is an LLC, filing federal Form 1120S. It's organized as a Wisconsin LLC and it is domiciled in Wisconsin. It is required to file a Wisconsin return. But all gross receipts - yes, all of them - are attributable to Indiana sources. So I'm filing two state returns: Indiana (Form IT-20S) and Wisconsin (Form 5S). When I do my state apportionment input, I've got 100% of revenue going to Indiana. Zero to Wisconsin. This situation produces e-file diagnostics on both state returns because apportionment percentages are generally greater than 0% and less than 100%. On Indiana, the return instructions specifically state, "Do not use 100%" on the line that specifies state apportionment. But the instructions do not tell you what to do if you actually do have 100% of gross receipts coming from Indiana sources. I could get out of this situation by pretending that 0.01% of the receipts are sourced to Wisconsin. The effect is not material. But I'm reluctant to do that because that doesn't accurately reflect the actual situation. It's something the client might notice and ask about.
I think there must be some correct way to handle this, and I'm just on the wrong track. Being in Texas, I haven't seen many multi-state returns before. Any state tax gurus out there that can give me some guidance on this?