Instructions for Form IL-1120 Corporation Income and Replacement Tax Return - Illinois

Form IL-1120 Schedule INS Tax for Foreign Insurers - Illinois

This document contains official instructions for Form IL-1120 , Corporation Income and Replacement Tax Return - a form released and collected by the Illinois Department of Revenue. An up-to-date fillable Form IL-1120 Schedule INS is available for download through this link.

FAQ

Q: What is Form IL-1120?
A: Form IL-1120 is the official tax return form for corporations in Illinois.

Q: Who needs to file Form IL-1120?
A: All corporations doing business in Illinois, including S corporations, must file Form IL-1120.

Q: What taxes does Form IL-1120 cover?
A: Form IL-1120 covers both the corporation income tax and the replacement tax.

Q: What is the due date for Form IL-1120?
A: Form IL-1120 is generally due on the 15th day of the 3rd month following the close of the tax year.

Q: Are there any extensions available for Form IL-1120?
A: Yes, corporations can request an extension of time to file Form IL-1120.

Q: How can I file Form IL-1120?
A: Form IL-1120 can be filed electronically or by mail.

Q: What supporting documents do I need to attach to Form IL-1120?
A: Corporations are generally required to attach a copy of their federal income tax return and any other supporting schedules or statements.