What federal forms must I attach to my IL-1120?

What federal forms must I attach to my Form IL-1120, Corporation Income and Replacement Tax Return?

When filing your return there are certain types of income items and subtraction modifications that require the attachment of Illinois or federal forms and schedules.  Instructions for these attachments appear throughout the specific IL-1120 instructions  for completing your return. 

All taxpayers, including unitary business groups, must attach a copy of your U.S. Form 1120, Pages 1 through 4, and Schedules L, M-1, M-2, and M-3, if applicable, or U.S. Form 1120-A, Pages 1 and 2 to your Illinois return.  However, there are a few exceptions:

• Exception 1 - If you are a life insurance company, nonlife mutual, or nonlife stock insurance company, you must attach a copy of U.S. Form 1120L, Page 1, or U.S. Form 1120-PC, Page 1 (and Schedule A, if filed).
• Exception 2 - If you are a corporation whose taxable income is included in a consolidated federal tax return, you must provide a pro forma copy of U.S. Form 1120, U.S. Form 1120-L, or 1120-PC, and all applicable schedules as if you had filed a separate federal return.

Note: When filing your Form IL-1120, include only forms and schedules required to support your return.  Please do not attach correspondence to your return. 

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