Connecticut State Department of Revenue Services

DRS will be holding a webinar on Wednesday, May 14, 2025, at 10:00 a.m.  This session will provide an overview of the sales and use tax requirements pertaining to swimming pool installation, repair, cleaning and maintenance services.  Select here to register.

2018 Corporation Tax Forms

Booklet

Name Description Revised Date
CT-1120 2018 Connecticut Corporation Business Tax Instructions 01/2018

Business Tax Returns

Name Description Revised Date
CT-1120 2018 Corporation Business Tax Return 12/2018
CT-1120A Corporation Business Tax Return Apportionment Computation (with instructions) 12/2018
CT-1120 ATT Corporation Business Tax Return Attachment Schedules H, I, and J (with instructions) 12/2018
CT-1120AB Add Back and Exceptions to Add Back of Interest and Intangible Expenses 12/2016
CT-1120K Business Tax Credit Summary 12/2018
CT-1120I Computation of Interest Due on Underpayment of Estimated Tax (with instructions) 12/2018
CT-1120 EXT Application for Extension of Time to File Corporation Business Tax Return (with instructions) 12/2018
CT-1120 ES 2019 Estimated Corporation Business Tax Payment Coupons 12/2018
CT-1120 ES 2018 Estimated Corporation Business Tax Payment Coupons 12/2017
CT-1120X Amended Corporation Business Tax Return 12/2018
CT-1120X Inst. Amended Corporation Business Tax Return Instructions 12/2018
CT-1120 CU BOOKLET 2018 Combined Unitary Corporation Business Tax Booklet 12/2018
CT-1120 CU 2018 Combined Unitary Corporation Business Tax Return 12/2018
CT-1120A-CU 2018 Apportionment Computation for Combined Unitary Filers 12/2018
CT-1120CU-NI 2018 Tax on Combined Group Net Income 12/2018
CT-1120CU-MTB 2018 Tax on Combined Group Minimum Tax Base 12/2018
CT-1120CU-MI 2018 Combined Group Member Information 12/2018
CT-1120CU-NCB 2018 Nexus Combined Base Tax Calculation 12/2018

Other Corporation Forms

Name Description Revised Date
AU-796 Reinstatement Guarantee Declaration for Non-stock Corporations 03/2008
AU-797 Dissolution Guarantee Declaration for Stock Corporations 04/2008
AU-800a Withdrawal Guarantee Declaration for Corporations 03/2008
AU-801 Reinstatement Guarantee Declaration for Stock Corporations 03/2008
CT-1120A-A Corporation Business Tax Return Apportionment Computation-Air Carriers 03/2017
CT-1120 A-BMC Corporation Business Tax Return Apportionment Computation - Motor Bus and Motor Carrier Companies 12/2016
CT-1120 A-BPE Corporation Business Tax Return Apportionment Computation - Broadcasters and Production Entities 12/2016
CT-1120 A-CCA Corporation Business Tax Return Apportionment Computation of Income From Credit Card Activities 12/2016
CT-1120 A-FS Corporation Business Tax Return Apportionment Computation of Income from Financial Service Companies Activities 12/2017
CT-1120 A-IRIC Corporation Business Tax Return Apportionment Computation of Income from Services to Regulated Investment Companies 12/2016
CT-1120 A-LP Corporation Business Tax Return Apportionment of Limited Partnership Interests 12/2017
CT-1120 A-SBC Corporation Business Tax Return Apportionment Computation - Securities Brokerage Services 12/2016
CT-1120 PIC Information Return for Passive Investment Companies 12/2018

Credit Forms

Name Description Revised Date
CT-1120 AT Apprenticeship Training Tax Credit 12/2018
CT-1120 DA Digital Animation Tax Credit 12/2018
CT-1120 DL Donation of Land Credit 12/2018
CT-1120 EDPC Electronic Data Processing Equipment Property Tax Credit 12/2018
CT-1120 FCIC Fixed Capital Investment Credit 12/2018
CT-1120FP Film Production Tax Credit 12/2018
CT-1120 FPI Film Production Infrastructure Tax Credit 12/2018
CT-1120 GB Green Building Tax Credit 12/2018
CT-1120 HCIC Human Capital Investment Credit 12/2018
CT-1120 HH Historic Homes Rehabilitation Tax Credit 12/2018
CT-1120 HP Historic Preservation Tax Credit 12/2018
CT-1120 HPC Housing Program Contribution Credit 12/2018
CT-1120 HR Historic Rehabilitation Tax Credit 12/2018
CT-1120 HS Historic Structures Rehabilitation Tax Credit 12/2018
CT-IRF Insurance Reinvestment Fund Credit 12/2018
CT-1120 MEC Machinery and Equipment Expenditure Credit 12/2018
CT-1120 PE Pass-Through Entity Tax Credit 12/2018 
CT-1120 RC Research and Experimental Expenditures Credit 12/2018
CT-1120 RDC Research and Development Credit 12/2018
CT-1120SF Service Facility Credit 12/2018
CT-1120 TIC-EZ Manufacturing Facility Credit for Facilities Located in a Targeted Investment Community/Enterprise Zone
NOTE: This form replaces Forms CT-1120 CRMC, CT-1120 CRMCEZ, CT-1120 MC and CT-1120 MCEZ		 12/2018
CT-UISR Urban and Industrial Site Reinvestment Credit 12/2018
CT-1120 XCH Application for Exchange of Research and Development or Research and Experimental 12/2018