CT-1120CU-NI: Tax on Combined Group Net Income (2025)
Connecticut · Connecticut DRS · Used for tax years 2025
Form CT-1120CU-NI is Connecticut’s Tax on Combined Group Net Income form. It reports corporate members’ income and deductions, combined group adjustments and eliminations, and the calculation of adjusted federal taxable income and combined group net income or loss.
Who files this form
Combined groups use Form CT-1120CU-NI to calculate their tax on the net income base. Complete it and attach it to Form CT-1120CU.
Combined groups are taxed on the greater of their net income base or their minimum tax base, also called the capital base.
Part I includes each taxable and nontaxable member. Part III includes only taxable members.
When it's due
The text does not give a filing deadline for the 2025 Form CT-1120CU-NI.
For the net deferred tax liability deduction on the 2025 form, a historical eligibility deadline applies: Form CT-DTLD must have been submitted to DRS on or before July 3, 2017. Companies that did not meet that deadline cannot claim the deduction. This is not the filing deadline for the 2025 return.
What you'll need
Have the following information and forms available, as applicable:
- The designated taxable member’s Connecticut tax registration number, plus corporation names and member numbers.
- Each member’s federal Form 1120 amounts, or the amounts it would have reported if it had filed that return.
- Form 4797, Part II, Line 17, for the gain or loss reported in Part I.
- Federal Form 4562 for claimed federal bonus depreciation.
- Form CT-1120 ATT, Schedules I and J, used as worksheets for the dividend deduction and bonus depreciation recovery.
- Form CT-1120A-CU, Schedule Q, Line 10, for each taxable member’s standard apportionment fraction, and any applicable special apportionment forms.
- Capital loss and net operating loss carryover amounts, if used.
- The timely submitted Form CT-DTLD, if claiming the net deferred tax liability deduction.
Attach explanations for entries on Part II, Lines 9 and 19. Attach extra copies of Page 2 if the group has more than six members, and Page 5 if it has more than eight taxable members.
How to file
Complete Form CT-1120CU-NI and attach it to Form CT-1120CU. Transfer the total from Part III, Line 14, to Form CT-1120CU, Part I, Line 1.
The supplied text does not specify a mailing address or an e-file method. It lists portal.ct.gov/DRS for more information.
Common mistakes
- Including nontaxable members in Part III. The instructions specifically say not to complete Part III columns for them.
- Exceeding the net operating loss limit. The deduction on Part III, Line 10, cannot exceed 50% of Line 8 in the same member’s column.
- Exceeding the deferred tax deduction limit. Part II, Line 22, must not exceed Line 21.
- Missing explanations. Attach an explanation for “Other” entries on Part II, Lines 9 and 19.
- Counting special-apportionment receipts in the standard calculation. Remove receipts from activities subject to separate apportionment from the standard apportionment calculation on Form CT-1120A-CU, Schedule Q.
Questions people ask
Does Part I include nontaxable members?
Yes. Complete a Part I column for each taxable and nontaxable member. Part III, however, includes only taxable members.
How are dividends between group members handled?
Dividends paid from one member to another are eliminated from the recipient’s income.
How is the tax calculated for each taxable member?
Multiply the member’s Part III, Line 12 amount by 7.5%. Other than for REITs and RICs, enter $250 if the result is less than $250.
How much of the net deferred tax liability deduction can be claimed?
Part II, Line 22, calls for one-thirtieth of the amount on Line 6 of a timely submitted Form CT-DTLD. The deduction cannot exceed Part II, Line 21.
Where does the final tax total go?
Add the amounts in all member columns on Part III, Line 13. Enter the total on Part III, Line 14, and on Form CT-1120CU, Part I, Line 1.