Instructions for Form CT-1120 — Corporation Business Tax Return

Department of Revenue Services

State of Connecticut

# Connecticut Corporation Business Tax

(Rev. 12/25)

# Return Instructions

For additional information on the Connecticut Corporation Business Tax, visit portal.ct.gov/DRS/Corporation-Tax/
Tax-Information.
Attach to Form CT‑1120 a completed copy of the corporation's federal income tax return, including all schedules and attachments as filed with the IRS.

# Required Information

Enter the beginning and ending dates of the corporation's income year regardless of whether the corporation is a calendar year or fiscal year filer. Also enter the corporation's Connecticut Tax Registration Number and FEIN.
Enter in the spaces provided the total assets from the corporation's federal Form 1120, U.S. Corporation Income Tax Return, Schedule L, Line 15, Column (d), and the amount from federal Form 1120, Line 11 (see Form CT‑1120, Schedule C, Line 1b). Also enter the North American Industry Classification System (NAICS) code for principal business activity.

# NAICS Code for Principal Business Activity

Enter the North American Industry Classification System (NAICS) code for your principal business activity. General information concerning the classification of principal business activity under NAICS can also be found at www.census.gov/naics.

# Payment Tax Credit

Credit to be Issued in the Form of a Refund
Application Procedure
Check the Yes box if the corporation is requesting a refund for the Student Loan Payment tax credit available under Conn.
Gen. Stat. § 12‑217qq. Enter the amount of credit to be issued in the form of a refund requested in the space provided on Page 1 of Form CT‑1120.
File Form CT‑RSLP, Application for Refund of Student Loan Payment Tax Credits by a Qualified Small Business, separately from Form CT‑1120. Attach Form CT‑SLP, Student Loan Payment Tax Credit, and all required supporting schedules and documentation to Form CT‑RSLP.
At the same time as filing Form CT‑1120, mail the completed application and supporting information to:
Department of Revenue Services
PO Box 150420
Hartford, CT 06115-0420

# Credits

Credit to be Issued in the Form of a Refund
Application Procedure
Check the Yes box if the corporation is exchanging Research and Development tax credits available under Conn. Gen. Stat.
§§ 12‑217j or 12‑217n, for a credit to be issued in the form of a refund, subject to certain limitations. Enter the amount of credit to be issued in the form of a refund requested in the space provided on Page 1 of Form CT‑1120.
File Form CT‑1120 XCH, Application for Exchange of
Research and Development or Research and Experimental
Expenditures Tax Credits by a Qualified Small Business, separately from Form CT‑1120. Attach Form CT‑1120RC, Research and Experimental Expenditures Tax Credit, or Form CT‑1120 RDC, Research and Development Expenditures Tax Credit, and all required supporting schedules and documentation to Form CT‑1120 XCH.
At the same time as filing Form CT‑1120, mail the completed application and supporting information to:
Department of Revenue Services

PO Box 150420

Hartford, CT 06115-0420

# Income

A corporation entitled to apportion its net income must complete either Form CT-1120A, Corporation Business Tax Return Apportionment Computation, or one of the special apportionment forms listed below:

Air carriers use Form CT-1120A-A, Corporation Business • Tax Return Apportionment Computation - Air Carriers.

Motor bus companies and motor carriers engaged in multistate business use Form CT-1120A-BMC, Corporation Business Tax Return Apportionment Computation - Motor Bus and Motor Carrier Companies.

Financial service companies use Form CT‑1120A‑FS, •

Corporation Business Tax Return Apportionment

Computation of Income From Financial Service Company
Activities.
Broadcasters and production entities use Form •

CT‑1120A‑BPE, Corporation Business Tax Return

Apportionment Computation - Broadcasters and
Production Entities.

Corporations that receive income from rendering securities brokerage services use Form CT‑1120A‑SBC, Corporation Business Tax Return Apportionment Computation -Securities Brokerage Services.
Corporations that receive income from credit card activities use Form CT‑1120A‑CCA, Corporation

Business Tax Return Apportionment Computation of
Income From Credit Card Activities.

If a corporation is a limited partner in one or more limited partnerships, other than an investment partnership, and is not otherwise carrying on or doing business in Connecticut, the partnership may elect for any income year to apportion its net income using Form CT‑1120A‑LP, Corporation

Business Tax Return Apportionment of Limited Partnership
Interests.

Corporations that receive income from rendering services to or on behalf of regulated investment companies use

Form CT‑1120A‑IRIC, Corporation Business Tax Return

Apportionment Computation of Income From Services to
Regulated Investment Companies.
Line 2 - Enter the appropriate apportionment fraction from Form CT‑1120A, Schedule Q, Line 9 or from the appropriate forms previously referenced. The fraction must be expressed as a decimal and carried to six places.

Line 3 - Enter the amount from Line 1 multiplied by Line 2, or enter the amount from Line 1, if not entitled to apportion.
Line 4 - Enter the amount of any unused losses from Form
CT‑1120 ATT, Corporation Business Tax Return Attachment, Schedule H, Line 22, Column E. Do not exceed 50% of Line 3.

# Capital

Use Schedule B to compute the minimum tax on the capital of a corporation. The minimum tax on capital cannot be less than $250 or exceed $1 million.
Financial service companies are subject to a minimum tax on capital of $250 and do not complete Schedule B. Real estate investment trusts, regulated investment companies, or interlocal risk management agencies formed under Chapter 113a of the Connecticut General Statutes are not subject to the minimum tax on capital and do not complete Schedule B.
Line 2 - Corporations, other than air carriers, enter the apportionment fraction from Form CT‑1120A, Schedule S, Line 3, Column C. Air carriers enter the amount from Form CT‑1120A‑A, Schedule R‑A, Line 5. The fraction must be expressed as a decimal and carried to six places.
Line 3 - Enter the amount from Line 1 multiplied by Line 2, or enter the amount from Line 1, if not entitled to apportion.
Line 4 - Enter the number of months the corporation carried on business or had the right to carry on business in Connecticut, whichever is greater. A fractional part of a month is counted as a full month.
Line 6 - Multiply Line 5 by 0.21%. The maximum tax for Schedule B is $1 million.

# Schedule C - Computation of Amount Payable

Line 1a - Enter the amount from Schedule A, Line 6;
Schedule B, Line 6; or $250, whichever is greater.
Line 1b - Multiply Line 1a by 10%. If the amount on Line 1a is $250 or the amount on federal Form 1120, Line 11 is less than $100 million, enter "0."
Line 1c - Enter the total tax credit that must be recaptured.
The following tax credits are subject to recapture:

Fixed Capital Investment; and
•

Urban and Industrial Site Reinvestment.

In most cases, other than the Fixed Capital Investment tax credit, the corporation will have been advised by the agency administering the tax credit that recapture is required.
A corporation is required to recapture the Fixed Capital Investment tax credit when the fixed capital is not held and used in Connecticut by the corporation for five full years following its acquisition. See Form CT‑1120 FCIC, Fixed Capital Investment Tax Credit, to calculate the amount of tax credit that must be recaptured. See the Guide to Connecticut Corporation Business Tax Credits available on the DRS website at portal.ct.gov/DRS.
Line 2 - Multiply Line 1 by 49.99%.
Line 5a - Enter the total tax credits applied from

Form CT‑1120K, Business Tax Credit Summary, Part II, Line 9. Do not exceed the amount on Line 4.
Line 5b - Enter the excess credit utilization from Form CT‑1120K, Part II, Line 17.
Line 7 - Enter the Pass‑Through Entity tax credit from
Schedule PE, Pass-Through Entity Credit Summary, Line 2.
Do not exceed the amount reported on Line 6.
Line 9a - Enter the amount paid with Form CT‑1120 EXT, Application for Extension of Time to File Connecticut Corporation Business Tax Return.
Line 9b - Enter the amount(s) paid with Forms CT‑1120 ESA,

# ESB, ESC, or ESD, Estimated Connecticut Corporation

Business Tax.
Line 9c - Enter the amount of any overpayment from the prior year.
Line 9d - Amended filers only. Enter the amounts paid with original return, plus additional tax paid after the original return was filed. Do not include penalty and interest.
Line 9e - Enter amount of Refundable tax credits from Form
CT-1120K, Part I-E, Line 5.
Line 10a - Amended filers only. Enter the overpayment, if any, as shown on original return or as previously adjusted.
All others enter zero ("0").
Line 11a - Enter penalty if applicable.
Line 11b - Enter interest due on tax not paid by the original due date.
Line 11c - Enter interest due on underpayment of estimated tax. Complete and attach Form CT‑1120I, Computation of Interest Due on Underpayment of Estimated Tax.
Line 12a - Enter the amount of overpayment to be credited to 2026 estimated tax.
The overpayment will be treated as estimated tax paid on the fifteenth day of the third month (March 15 for calendar year filers), if the tax return is filed on time or if the tax return is filed within the extension period if a timely request for extension was filed. A request to apply an overpayment to the following income year is irrevocable. For more information, see portal.ct.gov/DRS/Corporation-Tax/Tax-Information.
Line 12b - Enter the amount of overpayment to be refunded.
Lines 12c through 12e - Get the refund faster by choosing direct deposit. Complete Lines 12c, 12d, and 12e to have the refund directly deposited into a checking or savings account.
No. 101

Name of Depositor
Date

Street Address

City, State, Zip Code
Pay to the

$
Name of your Bank

Street Address

City, State, Zip Code
092125789 091 025 025413 0101
 

Account Number

# Routing Number

Enter the nine-digit bank routing number and the bank account number in Lines 12d and 12e. The bank routing number is normally the first nine-digit number printed on the check or savings withdrawal slip. The bank account number generally follows the bank routing number. Do not include the check number as part of the account number. Bank account numbers can be up to 17 characters.
If any of the bank information supplied for direct deposit does not match, or the applicable bank account is closed prior to the deposit of the refund, the refund will automatically be mailed.
Line 12f - Federal banking rules require DRS to request information about foreign bank accounts when the taxpayer requests the direct deposit of a refund into a bank account.

If the refund is requested to be deposited into a bank outside of the United States, DRS will mail the refund.

# Schedule D - Computation of Net Income

Line 1 - Enter the corporation's federal taxable income (loss) before net operating loss and special deductions as filed on the corporation's federal return.
Line 2 - Enter all interest income exempt from federal taxation.
Line 3 - Enter state and local income taxes deducted in the calculation of federal taxable income, including Connecticut Corporation Business Tax.
Line 4 - Enter the amount of interest expenses paid to a related member as reported on Form CT‑1120AB, Summary of Add Back and Exceptions to Add Back of Interest and Intangible Expenses, Part I A, Line 1.
Line 5 - Enter the amount of intangible expenses paid to a related member as reported on Form CT‑1120AB, Part I B, Line 3.
Line 6 - Enter the amount of the federal bonus depreciation allowed under IRC § 168(k) and claimed on federal Form 4562, Depreciation and Amortization.
Line 7 - Enter the amount of business interest expense that was incurred in a prior year and that was carried forward and deducted in the current year for federal tax purposes pursuant to IRC § 163(j).
Line 8 - Enter 80% of the IRC § 179 deduction claimed for federal tax purposes.
Line 9 - Enter any other income amount. Attach an explanation. Include the applicable amount of distributions from a manufacturing reinvestment account (MRA). Enter:

100% of distributions from an MRA to the extent they are used for non-qualifying purchases; and
100% of the money remaining in an MRA account that is returned to you after the five year period.

Line 11 - Enter the dividend deduction calculated on Form CT‑1120 ATT, Schedule I, Line 4.
Line 12 - Enter the amount of any available capital loss carryover not deducted in computing federal capital gain. This amount is limited to the amount of the capital gain reported on the federal return as described in Conn. Gen. Stat. § 12‑217.
Line 13 - Enter the value of any capital gain realized from the sale of any land, or interest in land, to the state, any political subdivision of the state, or to any nonprofit land conservation organization where such land is to be permanently preserved as protected open space or to a water company, as defined in Conn. Gen. Stat. § 25‑32a, where such land is to be permanently preserved as protected open space or as Class I or Class II water company land.
Line 14 - Enter the federal bonus depreciation recovery amount from Form CT‑1120 ATT, Schedule J, Line 26.
Line 15 - Enter the amount of exceptions to interest add back as reported on Form CT‑1120AB, Part II A, Line 1.
Line 16 - Enter the amount of exceptions to interest add back as reported on Form CT‑1120AB, Part II A, Line 2.
Line 17 - Enter the amount of exceptions to interest add back as reported on Form CT‑1120AB, Part II A, Line 3.
Line 18 - Enter the amount of exceptions to the add back of intangible expenses paid to a related member as reported on Form CT‑1120AB, Part II B, Line 1.
Line 19 - Enter 25% of IRC § 179 deduction that was added back in calculating Connecticut net income in the preceding four years.
Line 20 - Enter the amount of business interest expense that was incurred in the current year but was not allowed to be deducted for federal tax purposes pursuant to IRC § 163(j).
Line 21 - Enter the amount of any contributions made by the State of Connecticut or political subdivision thereof to the extent those contributions are included in Schedule D, Line 1 of this return.
Line 22 - For corporations that are licensed under Chapter 420f or 420h of the Connecticut General Statutes, enter the amount of ordinary and necessary business expenses allowed under IRC § 162 in determining the Connecticut corporation business tax liability.
Line 23 - Enter any other income deduction and attach an explanation. Other amounts should include the following:

The Foreign Derived Intangible Income (FDII) deduction claimed for federal purposes.
The amount of contributions to a manufacturing reinvestment account.
The amount received from a related member attributable to intangible expenses and costs or to interest expenses and costs, provided such income was:
Included on Schedule D, Line 1 of this return;
Received from a related member who filed a Connecticut Corporation Business Tax return for the same income year; and
Required to be added back by the related member under Conn. Gen. Stat. §§ 12‑218c or 12‑218d and was not entitled to an exception of the add back.
For all REITs, enter the deduction from federal Form 1120‑REIT, U.S. Income Tax Return for Real Estate Investment Trusts, Schedule J, Line 2f, only if such amount is equal to $50,000. In addition, for a REIT that is not a "captive REIT," enter the deduction for dividends paid from federal Form 1120‑REIT, Line 21b.

Line 25 - Subtract Line 24 from Line 10. Enter the result here and on Schedule A, Line 1.

# Base

Line 1 - Enter the beginning (Column A) and ending (Column B) values of the issued and outstanding capital stock including treasury stock at par or face value, fractional shares, scrip certificates, and payments on subscriptions.
See federal Form 1120, Schedule L, Line 22a and Line 22b.
Line 2 - Enter the beginning (Column A) and ending (Column B) values of paid‑in or capital surplus, including retained earnings. Any deficit must be reported as a negative number. See federal Form 1120, Schedule L, Lines 23, 24, and 25.
Line 3 - Enter the beginning (Column A) and ending (Column B) values of all surplus reserves. Attach a schedule of all surplus reserves to support the amounts shown on Line 3.
A reserve is an amount set aside or deducted from current or retained earnings for meeting future liabilities.
Line 4 - Add Lines 1, 2, and 3 in both Column A and Column B.
Enter in Column C the average of Column A and Column B.

Line 5 - Enter the total holdings of stock of private corporations Check and Complete all Applicable Boxes in Column A and Column B. Enter in Column C the average

Change of Address of Column A and Column B.

Check the Address change box, and go to
Attach a schedule that lists the beginning and ending book portal.ct.gov/DRS-myconneCT to change your address values of total holdings of stock of private corporations, including through myconneCT. Log in to myconneCT, open the treasury stock. The total book value of shares must equal More… menu, locate the Taxpayer Updates group, and select the amount claimed as a deduction on Schedule E, Line 5.
Manage Names & Addresses.
The book value of stock does not include the value of other assets acquired and held in connection with or incidental to

Return Status the ownership of such stock.

Check the corresponding box to indicate the type of return Private corporations means all non‑governmental being filed. corporations, whether closely or publicly held.
Line 6 - Subtract Line 5, Column C, from Line 4, Column C.
Enter the result here and on Form CT‑1120, Schedule B, Line 1.

# Schedule G - Additional Required Information

Attach a schedule of corporate officers' names, complete home addresses, and corporate titles.
Line 1 - Enter the Connecticut towns in which the corporation owns or leases, as lessee, real or tangible personal property or performed any services.
Line 2a - If the corporation transferred a controlling interest in an entity where the entity owns, directly or indirectly, an interest in Connecticut real property, the corporation (the transferor) may be subject to the controlling interest transfer tax. Enter the name and FEIN of the entity in which a controlling interest was transferred. The transferor is required to file Form AU‑330, Controlling Interest Transfer Taxes.
Line 2b - If this corporation owned Connecticut real property • • • •
Initial
If this is the first time the corporation is filing Form CT‑1120, check the Initial box.
Amended
If the corporation is filing an amended return, check the Amended box and check the box to indicate the reason for amending. If the return is being amended to report a federal change, enter the date that the IRS made its final determination.
Final
If the corporation is filing a final return, check the Final box and complete Line 3, below.
Short Period
If the corporation is filing a short period return, check the Short period box.

Final Return and was the entity in which a direct or indirect controlling Check the corresponding box providing the reason for the interest was transferred, enter the name and FEIN or SSN of final return: the transferor. The transferor may be subject to the controlling interest transfer tax.

Line 2c -Enter the transferee(s) name(s) and the transfer date if the answer was Yes to either Line 2a or Line 2b. Attach a list of property addresses of the Connecticut realty owner according to the above transfer.
The entity in which a direct or indirect controlling interest was transferred is required to file Form AU‑331, Controlling Interest Transfer Taxes Informational Return.
Line 3 - If any other corporation owns a majority of the voting stock of this corporation, enter the name and FEIN of the corporation.
Line 4 - Enter the last taxable year this corporation was audited by the IRS. Corrections to taxable income by the IRS must be reported to the Commissioner of Revenue Services on or before 90 days after the final determination of the change.
Schedule PE - Pass-Through Entity ("PE")

# Credit Summary

Line 1 - Enter the PE credit carryforward from 2024 Form
CT-1120PE, Line 3.
Line 2 - Enter the amount of PE credit applied to the Corporation Business Tax. Any PE credit that exceeds the balance of tax due after other tax credits are applied may be carried forward to succeeding income years. Do not exceed the amount reported on Form CT‑1120, Schedule C, Line 6.
Line 3 - Carryforward to 2026: Subtract Line 2 from Line 1.
•
•
Dissolution
To properly dissolve a domestic corporation you must file a Certificate of Dissolution with the Connecticut Office of the Secretary of the State. A dissolved corporation must file a return for the period up to the date of legal dissolution or the date of the final liquidation of assets, whichever is later.
Any dissolved corporation that continues to conduct business must file Form CT‑1120 and pay any taxes due. If a corporation has been dissolved by forfeiture and wishes to be reinstated, it must submit a written request for a tax clearance to:

Department of Revenue Services

State of Connecticut

Corporation Tax Audit Unit
450 Columbus Blvd Ste 1

Hartford CT 06103-1837
The tax clearance and certificate of reinstatement must be filed with the Connecticut Office of the Secretary of the State.

# Withdrawal From State

A foreign corporation that wishes to withdraw from Connecticut must file a written application for withdrawal with the Connecticut Office of the Secretary of the State.
Any corporation that has withdrawn must file Form CT‑1120 up to the date of withdrawal and pay any taxes due.

Mergers and Reorganizations

A corporation that has merged must file a written application with the Connecticut Office of the Secretary of the State. Any corporation that has merged must file Form CT‑1120 covering the period up to the date of merger and pay any tax due.
Any organization that is reorganized must submit the details concerning the reorganization in writing and disclose the survivor's Connecticut Tax Registration Number to:

# DRS Operations Bureau/Registration

450 Columbus Blvd Ste 1

Hartford CT 06103-1837
If the corporation already has a Connecticut Tax Registration Number, additional taxes for which the corporation is liable may be added to the registration by contacting the DRS at 800‑382‑9463 (Connecticut calls outside the Greater Hartford calling area only); or 860‑297‑5962 (from anywhere).
For further information about withdrawal from the state, mergers and reorganizations, or dissolutions, contact the Connecticut Office of the Secretary of the State at 860‑509‑6003.

# 4. Type of Federal Return Filed

Check the appropriate box for the type of federal return filed.
If the Consolidated Basis box is checked, you must enter the parent company's name and FEIN.
An S corporation should file Form CT‑1065/CT‑1120SI, Connecticut Composite Income Tax Return and Addendum.
A limited liability company (LLC) should file Form CT‑1120 only if the company elects to be taxed as a corporation for federal income tax purposes.

5. Previous Combined Unitary Return
Indicate whether the corporation filed as part of a combined return on Form CT‑1120CU, Combined Unitary Corporation Business Tax Return, for the previous income year and is no longer a member of the combined group.

6. Non-Unitary Business Income
Indicate if the corporation files as part of Form CT‑1120CU, Combined Unitary Corporation Business Tax Return, in the current income year and is filing this Form CT‑1120 to report non-unitary business income.

# 7. Principal Place of Business

If the principal place of business is located outside Connecticut, enter the name of the state where it is located.
Enter the state in which the corporation filed its Articles of Incorporation and the date of organization. If incorporated outside of Connecticut, enter the date qualified to do business in Connecticut. A corporation must enter the date it began business operations in Connecticut.

8. Exempt Corporation
If the corporation is exempt from Connecticut Corporation Business Tax, check this box and attach an explanation of the exemption, and a statutory cite for the exemption.

# 9. Annualization

Check the corresponding box if the corporation used the annualized installment method to calculate its estimated tax payments for this year.
Complete Form CT‑1120I, Computation of Interest Due on Underpayment of Estimated Tax, and attach it to Form CT‑1120. For more information, see portal.ct.gov/DRS/
Corporation-Tax/Tax-Information.

10. Interest Add Back
Check the corresponding box if the corporation paid, accrued, or incurred interest expenses or intangible expenses, costs, and related interest expenses to a related member. Complete

Form CT‑1120AB, Summary of Add Back and Exceptions to Add Back of Interest and Intangible Expenses, and attach it to Form CT‑1120.

# Signature

The return must be signed by a duly authorized officer.

# Paid Preparer Signature

A paid preparer must sign and date Form CT‑1120. Paid preparers must also enter their Social Security Number (SSN) or Preparer Tax Identification Number (PTIN) and their firm's FEIN in the spaces provided.

# Paid Preparer Authorization

If the corporation wants to authorize DRS to contact the paid preparer who signed the 2025 Connecticut Corporation Business Tax Return to discuss it, check the Yes box in the signature area of the return. This authorization applies only to the individual whose signature appears in the Paid preparer's signature section of the return. It does not apply to the firm, if any, shown in that section.
If the Yes box is checked, the corporation is authorizing DRS to contact the paid preparer to answer any questions that may arise during the processing of the 2025 Connecticut Corporation Business Tax Return. The corporation is also authorizing the paid preparer to:

Give DRS any information that is missing from the return;
Contact DRS for information about the processing of the corporation's return or the status of the corporation's refund or payment; and
Respond to certain DRS notices that the corporation may have shared with the preparer regarding math errors, offsets, and return preparation. The notices will not be sent to the preparer.

The corporation is not authorizing the paid preparer to receive any refund check, bind the corporation to anything, including additional tax liability, or otherwise represent the corporation before DRS. The authorization cannot be revoked. However, the authorization will automatically end no later than the due date, without regard to extensions, for filing the 2025 Connecticut Corporation Business Tax Return. This is on or before the fifteenth day of the month following the due date of the corporation's corresponding federal income tax return for the income year (May 15 for calendar year filers).