CT-1120 GB: Green Building Tax Credit (2024)
Connecticut · Connecticut DRS · Used for tax years 2024
Form CT-1120GB is used to claim Connecticut’s Green Building Tax Credit against the Corporation Business Tax for eligible construction, renovation, or rehabilitation projects. The 2024 form reports credits carried forward from earlier years, credits applied to 2024, and the remai
Who files this form
Use the 2024 Form CT-1120GB to claim the Green Building Tax Credit against Connecticut Corporation Business Tax for eligible construction, renovation, or rehabilitation projects.
To be eligible, an application must have been submitted to and approved by the Department of Energy and Environmental Protection (DEEP) before December 1, 2017. An eligible project must be designed to meet the applicable LEED Gold certification or an equivalent certification determined by DEEP.
The credit may also be assigned to another taxpayer or taxpayers.
When it's due
For the 2024 credit claim, the form lists these historical eligibility requirements:
- The application must have been submitted to and approved by DEEP before December 1, 2017.
- Total credits claimed cannot exceed the amount of the tax credit voucher issued by DEEP before December 1, 2017.
The form does not print a filing due date for tax year 2024.
What you'll need
Have the following information available to complete the 2024 form:
- Corporation name, Connecticut Tax Registration Number, and income-year beginning and ending dates.
- The 2019 Green Building Tax Credit amount from 2019 Form CT-1120GB, Part I, Line 7.
- The 2020 Green Building Tax Credit amount from 2020 Form CT-1120GB, Part I, Line 5.
- Credit amounts applied to 2019 through 2020, carried forward to 2024, and applied to 2024.
- The DEEP tax credit voucher amount, which limits the total credits that may be claimed.
The text does not state that these records must be attached.
Common mistakes
- Using the wrong year's form: Each form is year specific. Use the 2024 version for the 2024 claim.
- Using the wrong ink or staples: Complete the form in blue or black ink only. Do not use staples.
- Exceeding the credit limits: A taxpayer may claim only 25% of total allowable costs in any year. Total credits claimed cannot exceed the DEEP voucher amount.
- Including excluded costs: Land purchases, remediation costs, telephone systems, and computers are not allowable costs.
- Leaving out shared credits: Members included in the 2024 Form CT-1120CU must include in Column D credits shared to and used by another member of the combined group.
- Carrying the credit back: No carryback is allowed.
Questions people ask
What credit percentage applies to my project?
For new construction or major renovation, the percentage is 8% for LEED Gold and 10.5% for LEED Platinum. For core and shell or commercial interior projects, it is 5% for Gold and 7% for Platinum. The credit equals allowable costs multiplied by the applicable percentage, subject to the form's limits.
Can the credit percentage increase?
Yes. It increases by 0.5% if the project meets any one of these conditions: it is a mixed-use development; it is in a brownfield or enterprise zone; it does not require a sewer extension of more than 1/8 mile; or it is within 1/4 mile walking distance of bus transit, rail, light rail, streetcar, or ferry services.
Can I use an unused credit in another year?
An unused credit balance may be carried forward for up to five income years. No carryback is allowed. On the 2024 form, the carryforward to 2025 comes from the 2020 credit row, calculated by subtracting Column D from Column C.
Can a project owner transfer the credit?
Yes. The credit may be assigned to another taxpayer or taxpayers. A project owner, including a nonprofit entity, may transfer a credit to a pass-through partner in return for a lump-sum cash payment.