CT-1120 CU: Combined Unitary Corporation Business Tax Return (2024)
Connecticut · Connecticut DRS · Used for tax years 2024
Form CT-1120CU is Connecticut’s 2024 Combined Unitary Corporation Business Tax Return. It reports the group’s members, combined tax, tax credits, payments, and any balance due or overpayment to be credited or refunded.
What you'll need
Have these forms and details ready:
- The designated taxable member’s name, address, Connecticut tax registration number, and federal employer identification number (FEIN).
- Member names, taxable status, Connecticut tax registration numbers, and FEINs for the member schedule. The parent and all taxable members must have Connecticut tax registration numbers included.
- Form CT-1120CU-NI and Form CT-1120CU-MTB for the amounts used in Part I. Complete Form CT-1120CU-NCB if Part I, Line 3 exceeds $2,500,000.
- A 2024 Form CT-1120K for each member claiming, using, or sharing a business tax credit. Attach these forms for Schedule KU.
- Form CT-1120I, which must be attached if the group annualized its estimated tax payments.
- Amounts paid with Form CT-1120 EXT and Forms CT-1120 ESA, ESB, ESC, and ESD, plus any prior-year overpayment.
- For an amended return, amounts paid with the original return, additional tax paid afterward, and any overpayment shown on the original return or as previously adjusted.
- Net operating loss and pass-through entity tax credit amounts requested in the summaries.
For direct deposit, have your account type, routing number, account number, and bank name ready.
How to file
The supplied form does not give a mailing address or electronic filing instructions. It does include these directions:
- Complete Part I, Part II, and Schedule KU before completing Part III.
- Complete and submit the member schedule on page 2 only if filing a paper return. List taxable members first.
- Attach a 2024 Form CT-1120K for each member claiming, using, or sharing a business tax credit.
- If a member is exchanging R&D tax credits, file Form CT-1120 XCH separately.
- If a member is requesting a refund for the Student Loan Payment tax credit, file Form CT-RSLP separately.
- Complete the corporate officer’s signature and date fields and keep a copy of the return for your records.
The form directs filers to portal.ct.gov/DRS for more information.
Common mistakes
- Using the wrong year’s form. DRS warns that each form is year-specific and that using the wrong year can delay processing of the return or refund.
- Leaving out required registration numbers. Include the Connecticut tax registration number for the parent and all taxable members.
- Completing Part III too soon. Complete Part I, Part II, and Schedule KU first.
- Exceeding the printed credit limits. In Part II, Line 3 cannot exceed Line 2 in any column, and Line 6 cannot exceed Line 5 in any column.
- Not keeping a copy. The form reminds you to keep a copy of the return for your records.
Questions people ask
Which filing methods are listed on the form?
Water’s Edge is marked as the default. Affiliated Group and Worldwide are marked as elections.
Can I receive my refund by direct deposit?
Yes. The form says to complete Lines 9c through 9e for a faster refund by direct deposit. These lines request the account type, routing number, and account number. It also asks whether the refund will go to a bank account outside the U.S. and requests the bank name.
Can I apply an overpayment to next year’s estimated tax?
The 2024 form includes Line 9a for the amount to be credited to 2025 estimated tax and Line 9b for the amount to be refunded.
What if the group has more than 50 members?
For a paper return, attach replicas of page 2 as needed, with the same information, and begin numbering the additional members with 51.