E-filing forms
E-file mandate
For tax periods beginning on or after January 1, 2014, the State of Connecticut requires that all composite income tax returns be filed electronically.
Forms included in the e-file
The state of Connecticut and UltraTax CS support electronic filing for the following forms:
- Calendar, fiscal and short year Form CT-1065/CT-1120SI
- Form CT-1065/CT-1120SI EXT, Extension
Form OP-424, Business Entity Tax is a biennial return and must be filed using the Taxpayer Service Center (TSC) unless a waiver is granted.
Forms not supported for e-filing
Connecticut doesn’t support PDF attachments to be included in the electronic file and doesn’t support electronic filing for the following:
- Amended returns
- Estimates
Payment methods
The State of Connecticut requires all tax payments to be made electronically. The state supports EFW, EFT, and credit card payments for balance due returns and direct deposit of refunds.
A payment on an electronically filed extension can only be made by electronic funds withdrawal (EFW). An extension can't be e-filed when the partnership wants to pay via electronic funds transfer (EFT).
