Thanks! I could have swore I read somewhere last year that I didn't need to file because I had no activity. This year the instructions for the 1120-ST Illinois return reads as follow:
"Who must file Form IL-1120-ST?
You must file Form IL-1120-ST if you are a small business
corporation (“S corporation”), as defined in Internal Revenue
Code (IRC) Section 1361(a), that
• has net income or loss as defined under the Illinois Income Tax
Act (IITA); or
• is qualified to do business in the state of Illinois and is required
to file U.S. Form 1120S (regardless of net income or loss).
If you own a Qualified Subchapter S Subsidiary (QSSS) defined
in IRC Section 1361(b)(3), as well as any other entity that is
disregarded as an entity separate from you for purposes of the
IRC, it is likewise disregarded as a separate entity for purposes
of the IITA. You must include all items of income, deduction, loss,
credit, etc., from such entities on your return as if they were
earned or incurred by you directly.
If you are an S corporation that is a member of a unitary business
group, see the instructions for Illinois Schedule UB, Combined
Apportionment for Unitary Business Group, and “What if I am a
member of a unitary group?” in the general instructions below
for information about filing requirements. S corporations may be
required to apportion their business income as members of a
unitary group, but cannot file a combined return."
This indicated to me that I need to file. However, my concern is that if I file this year, they will realize I didn't file last.