Upcoming CT DRS webinar: Select to register for the upcoming Withholding Tax Overview Webinar on Wednesday, July 24, 2024, at 10:00 a.m.

Other Helpful Information

Other Taxes for Which the Corporation May be Liable

Note: Additional taxes for which the corporation is liable may be added to the registration online through myconneCT.

Connecticut Income Tax Withholding

Any corporation that maintains an office or transacts business in Connecticut (regardless of the location of the payroll department) and is considered an employer for federal income tax withholding purposes must withhold Connecticut income tax from Connecticut wages as defined in Conn. Agencies Reg. § 12‑706(b)‑1. See the current edition of the Connecticut Employer’s Tax Guide, Circular CT.

Connecticut Sales and Use Taxes

A corporation may be responsible for filing sales and use tax returns. Sales tax is due if the company sells taxable goods or services. Use tax is due on the purchase of taxable goods or services from out-of-state retailers or Connecticut retailers who have not collected the sales tax. Use Form OS‑114, Connecticut Sales and Use Tax Return, to report both sales tax and business use tax.

Controlling Interest Transfer Tax

Tax is imposed on the sale or transfer for consideration of a controlling interest in an entity where the entity owns, directly or indirectly, an interest in Connecticut real property. This tax is reported on Form AU‑330, Connecticut Controlling Interest Transfer Tax Return.

Electronic Filing and Payment Waiver

If a corporation can show that filing and paying electronically creates an undue hardship, the Commissioner of Revenue Services may grant a one‑year waiver of the electronic filing and payment requirement. Request a waiver by completing Form DRS‑EWVR, Electronic Filing and Payment Waiver Request, no fewer than 30 days before the due date of your first electronic filing and payment. See Policy Statement 2020(2), Requests for Waiver of Electronic Filing and Electronic Payment Requirements.

File a Paper Return

A paper return may be filed only if a waiver from the electronic filing requirement has been granted. To apply for a waiver from the electronic filing requirement, complete Form DRS‑EWVR, Electronic Filing and Payment Waiver Request. See Electronic Filing and Payment Waiver for more information.

If you file a paper return, print in blue or black ink, or type the information requested in the space provided at the top of Form CT‑1120 or Form CT-1120CU.

Mail paper return with payment to:

Department of Revenue Services
State of Connecticut
PO Box 2974
Hartford CT 06104‑2974

Mail paper return without payment to:

Department of Revenue Services
State of Connecticut
PO Box 150406
Hartford CT 06115‑0406

Make check payable to Commissioner of Revenue Services. To ensure payment is applied to the correct account, write “2023 Form CT-1120” and the corporation’s Connecticut Tax Registration Number on the front of the check. For Form CT-1120CU, write "2023 Form CT-1120CU" and the designated taxable member Connecticut Tax Registration Number on the front of the check. Be sure to sign your check and paper clip it to the front of your return. DRS may submit your check to your bank electronically. Do not send cash.

The return will meet the timely filed and timely payment rules if the U.S. Postal Service cancellation date, or the date recorded or marked by a designated private delivery service (PDS) using a designated type of service, is on or before the due date. Not all services provided by these designated PDSs qualify. See Policy Statement 2016(4), Designated Private Delivery Services and Designated Types of Service, for a current list of qualified PDSs.

If Form CT‑1120 or Form CT-1120CU is filed late, see Interest and Penalties to determine if interest and penalty should be reported with this return.

Waiver of Penalty

To make a penalty waiver request, complete and submit Form DRS-PW, Request for Waiver of Civil Penalty, to the DRS Operations Bureau/Penalty Waiver through myconneCT, by mail, or fax.

For more information about the penalty waiver process, see Penalty waiver request, offer in compromise or protest (ct.gov)

Obtain Tax Clearance

  • IP 2018(10), Successor Liability and Request for Tax Clearance
  • AU-866, Request for a Tax Clearance Certificate

Rounding Off to Whole Dollars

You must round off cents to the nearest whole dollar on your return and schedules. If you do not round, DRS will disregard the cents. Round down to the next lowest dollar all amounts that include 1 through 49 cents. Round up to the next highest dollar all amounts that include 50 through 99 cents. However, if you need to add two or more amounts to compute the amount to enter on a line, include cents and round off only the total. 

Example: Add two amounts ($1.29+$3.21) to compute the total ($4.50) to enter on a line. $4.50 is rounded to $5.00 and entered on a line.


Keep a copy of the tax return, worksheets, and records of all items appearing on the return until the statute of limitations expires for that return. Usually, this is three years from the date the return was due or filed, whichever is later. However, if the corporation reports a net operating loss or credit carryforward or carryback, the statute of limitations may expire later.

Closing Corporation Business Tax

You may not close the corporation business tax account until you dissolve (if a domestic corporation) or withdraw (if a foreign corporation) with the Connecticut Secretary of the State.  You may download the appropriate forms for dissolution or withdrawal on the Secretary of State's website or contact the Office of the Secretary of the State for information and forms at 860-509-6000.

Remember, you are required to file a final Form CT-1120, Connecticut Corporation Business Tax Return. The corporation business tax applies to any year or part of a year when the corporation was in existence.

Power of Attorney

To authorize one or more individuals to represent you or your business before the Department of Revenue Services (DRS), use LGL-001, Power of Attorney. This authorization allows your representative(s) to receive and inspect confidential tax information and to act on your behalf in matters before DRS.

Submit LGL-001 electronically by sending it to DRS through a secure web message in myconneCT. Log in to myconneCT, open the More … menu, locate the Correspondence group and click the Send a Message hyperlink.

Change of Address

Taxpayers can change their address through myconneCT.

  1. Log in to myconneCT.
  2. Open the More... menu.
  3. Locate the Taxpayer Updates group and click the Manage Names & Addresses hyperlink.
  4. Continue to follow the prompts on the screen.