CT-1120CU-NCB: Nexus Combined Base Tax Calculation (Revision 2024-12)
Connecticut · Connecticut DRS · Used for tax years 2024
Form CT-1120CU-NCB calculates Connecticut nexus combined net income, the minimum tax base, and the tax on each. It also calculates the aggregate maximum tax and allocates it among taxable members for reporting on Form CT-1120CU.
Who files this form
For tax year 2024, use Form CT-1120CU-NCB if Form CT-1120CU, Part I, Line 3 is greater than $2,500,000 to determine whether the combined group’s tax is capped below the standard combined unitary tax amount.
- Do not complete this form if that amount is $2,500,000 or less.
- If the calculation affects the tax due, complete and attach this form to Form CT-1120CU.
- If the group determines that the calculation does not affect the tax due, it is not required to file this form, even if the amount exceeds $2,500,000.
What you'll need
Have the following forms and information available, as applicable:
- Form CT-1120CU and Form CT-1120CU-NI for the group’s tax amounts and allocation among taxable members.
- Each taxable member’s federal return, including federal Form 4562 for bonus depreciation.
- Form CT-1120, Schedules D and E, for taxable income and minimum tax base figures.
- Form CT-1120AB for related-member expenses and add-back exceptions.
- Form CT-1120 ATT, Schedules I and J, for dividends and bonus depreciation recovery.
- Form CT-1120A, Schedule Q, or the appropriate apportionment form.
- Schedules supporting capital loss and operating loss carryovers. The form requires these schedules to be attached.
- Explanations for amounts entered as “Other” on Part I, Lines 9 and 23. Attach these explanations.
You will also need the designated taxable member’s Connecticut tax registration number, corporation names, and taxable member numbers.
How to file
If applicable, complete Form CT-1120CU-NCB and attach it to Form CT-1120CU.
Enter the aggregate maximum tax from Part III, Line 5 on Form CT-1120CU, Part I, Line 4. Enter each member’s allocation from Part III, Line 9 in the corresponding column on Form CT-1120CU, Part I, Line 6c.
If the group later determines that this calculation affects the tax due, it may file the form with an amended return or provide it to DRS during an audit examination.
Common mistakes
- Completing the form when Form CT-1120CU, Part I, Line 3 is $2,500,000 or less. The instructions say not to complete it in that case.
- Failing to carry apportionment fractions to six decimal places.
- Including receipts from other taxable members in the same combined unitary return when calculating the receipts factor. The instructions say to exclude these receipts.
- Omitting required explanations for “Other” amounts or schedules for loss carryovers.
- Exceeding the $1,000,000 maximum tax on the nexus combined minimum tax base.
Questions people ask
What does this form calculate?
It calculates whether the combined group’s tax liability is capped at an amount lower than the tax calculated on the standard combined unitary basis.
How is the aggregate maximum tax calculated?
Part III takes the larger of the tax on nexus combined net income and the tax on the nexus combined minimum tax base, then adds $2,500,000. The cap applies before surtax and credits.
Does the group always use the aggregate maximum tax?
No. The group uses it only if it is less than the standard combined unitary tax reported on Form CT-1120CU, Part I, Line 3. Otherwise, the standard combined unitary tax applies.
What tax rates appear on the form?
Part I multiplies nexus combined income subject to tax by 7.5%. Part II multiplies the nexus combined minimum tax base by 0.0026, with a maximum tax of $1,000,000.