CT-1120 ATT: Corporation Business Tax Return Attachment Schedules H, I, and J (2025)
Connecticut · Connecticut DRS · Used for tax years 2025
Form CT-1120 ATT contains attachment Schedules I, H, and J for the 2025 Connecticut Corporation Business Tax Return. These schedules calculate the dividend deduction, track Connecticut apportioned loss carryovers, and calculate bonus depreciation recovery.
Who files this form
Attach Form CT-1120 ATT to Form CT-1120 whenever Schedule H, I, or J is used to calculate Connecticut Corporation Business Tax:
- Schedule H: Connecticut apportioned operating loss carryover.
- Schedule I: Dividend deduction.
- Schedule J: Bonus depreciation recovery. Complete this schedule if the corporation claimed IRC § 168(k) bonus depreciation for qualifying property on federal Form 4562.
Corporations filing as part of Form CT-1120CU use the applicable schedules as worksheets. Do not file or attach Form CT-1120 ATT to Form CT-1120CU.
What you'll need
Have the information needed for the schedules you use:
- Corporation details: Corporation name and Connecticut Tax Registration Number.
- Schedule H: Prior-year Forms CT-1120 showing Connecticut apportioned operating losses, amounts already used, and any losses shared with or received from unitary affiliates.
- Schedule I: Dividend income included in federal taxable income, including Subpart F inclusions and GILTI amounts, and the amount of dividends from domestic corporations owned less than 20%.
- Schedule J: Federal Form 4562 and depreciation calculations for qualifying assets, including their placed-in-service years and 2025 MACRS depreciation on both the federal and Connecticut bases.
How to file
Electronically: File Form CT-1120 ATT with Form CT-1120 using myconneCT.
By mail: Complete the form in blue or black ink only. Do not use staples. Use the 2025 form for tax year 2025 and attach it to Form CT-1120 when any of these schedules is used in the tax calculation.
Combined unitary filers: Use the schedules as worksheets only. Do not file or attach Form CT-1120 ATT to Form CT-1120CU.
Common mistakes
- Entering negative numbers: Do not enter negative numbers in any column. Schedule H requires losses to be entered as positive numbers.
- Using the wrong year's form: The instructions warn that submitting the correct year's form is required to prevent processing delays.
- Using staples or the wrong ink when mailing: Use blue or black ink only and do not staple the form.
- Attaching the worksheet to a combined unitary return: Do not file or attach Form CT-1120 ATT to Form CT-1120CU.
- Exceeding the operating loss limit: Schedule H, Line 22 cannot exceed 50% of Form CT-1120, Schedule A, Line 3, or 50% of Form CT-1120CU-NI, Part III, Line 8.
- Using Schedule H's sharing columns for a separate return: Columns D and F apply only to members filing as part of Form CT-1120CU.
Questions people ask
How long can operating losses be carried forward?
Losses incurred in income years beginning on or after January 1, 2000 and before January 1, 2025 may be carried forward for 20 successive income years. Losses incurred in income years beginning on or after January 1, 2025 may be carried forward for 30 successive income years.
How are related expenses calculated for the dividend deduction?
For Schedule I, Lines 2 and 3, multiply Column A by 5% and enter the result in Column D. Subtract Column D from Column C to find the dividend deduction in Column E.
Are dividends from a real estate investment trust included on Schedule I, Line 1?
Generally, they are excluded. Include them if they are deductible under IRC § 243 or are received by a qualified dividend recipient from a qualified real estate investment trust.
How is bonus depreciation recovery calculated on Schedule J?
Column A shows 2025 MACRS depreciation on the federal basis after IRC § 168(k) bonus depreciation. Column B shows 2025 MACRS depreciation on the Connecticut basis without that bonus depreciation. Subtract Column A from Column B for each entry in Column C, then total Lines 1 through 25 in Column C on Line 26. For Form CT-1120 filers, transfer that total to Schedule D, Line 14.