1120 Illinois frequently asked questions

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MFA required for electronic filing

Effective May 3rd, the 2017 version of UltraTax CS requires multi-factor authentication (MFA) to transmit e-files from CS Connect. Find out more.

Known open issues

New for 2017

See also: 2017 Illinois user bulletins

Frequently asked questions

Annual Reports

Entering state or country of incorporation


Calculating apportionment

Calculating apportionment on Schedule UB, Step 4

Entering 1120 apportionment data for consolidated or combined states

Combined returns

Estimated payments for a combined unitary return

Extending a combined unitary return

Filing a combined unitary return

Preparing a unitary return

Electronic filing

State Electronic Filing Guide

Electronically filing consolidated or combined returns

Estimate electronic filing

Filing Illinois estimates electronically

Forms supported for electronic filing

Forms and schedules not supported for electronic filing

Officer Social Security number

PDF attachments automatically included with electronic file

Receiving an alert in a state acknowledgement

Required by the Department of Revenue when electronically filing a corporate return


Form IL-505-B will not print

Forms approval

Viewing forms approval status

Luxury auto treatment on Form IL-4562

Luxury auto treatment on Form IL-4562

Net loss deduction

Current net loss carryforward rules

Limitations for the amount of Illinois net loss deduction used to offset income

ILDOR determines the loss year that expires first

S Corporations

Indicating a shareholder as a nonresident

Printing Schedules B and K-1-P

Making prepayments for S Corporations

Unitary returns

Preparing a unitary return with C corporation and pass-through members

Preparing a unitary return consisting of only pass-through members

Filing a unitary return

Extending a unitary return

Making estimated payments for a unitary return

Determining a designated agent for a unitary return

Data sharing a unitary member’s information

Unitary return is not supported for electronic filing

Related topic: 1120 frequently asked questions

Internal notes

Release notes

Version Date Available Notes
17.2.0 1/5/18 Initial release
17.2.1 1/22/18 Update
17.3.0 2/2/18 Update
17.3.1 2/15/18 Update
17.3.2 3/9/18 Update

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