idaplanner wrote:@CathysTaxes - did you ever get to the bottom of this IL issue? Do they really have the right to double tax the same income as another state taxes, and not give a credit (partial due to difference in tax rates) for the tax paid to the other state? I have a client who got the dreaded letter from the ILDOR disallowing the credit for tax paid to another state, basically saying they tax all IL income because his home office is in IL, even though he travels to another state to do the majority of the work and pays tax in that other state.
I'm still waiting to hear from the client to see if our challenge was accepted. The employer submitted a letter (on their letterhead) that specifically stated how much of the money was sourced to Illinois. The employer has since changed payroll providers and 2016 W2s did not need the letter.