DRS: Corp & S Corp Info

Corporation & S Corporation Tax Information
Corporation Registration Requirements:   Any corporation that carries on business in Connecticut or has the right to carry on business in Connecticut must register for Connecticut tax purposes with the Department of Revenue Services.  That includes any corporation that is formed with the Connecticut Secretary or the State and any corporation formed outside of Connecticut but who meets the nexus criteria in Sec.12-214-1 of the Regulations of Connecticut State Agencies. Businesses must register for the corporation business tax by completing the appropriate section of Form REG-1 , Business Taxes Registration Application . There is no fee for registering for the Corporation Business Tax. 
  • If the corporation elects S corporation status, it must indicate that on Form REG-1. (See S Corporation Election, below.) S corporation tax requirements are listed below.
  • If the corporation was issued a federal Determination Letter of exemption under Section 50l(c)(3) or (13) of the Internal Revenue Code, it must also indicate that on Form REG-1.  Any corporation granted nonprofit status by the IRS is also exempt from Connecticut corporation business tax. It must, however, register with DRS.
  • If the corporation elects S corporation status with the Internal Revenue Service after it registers with DRS, it must notify DRS of the change in its status. 
Corporation Business Tax Filing Requirements:  A corporation must file Form CT-1120, Connecticut Corporation Business Tax Return, if it carries on business or has the right to carry on business in Connecticut. Any corporation dissolved or withdrawn from Connecticut is subject to the corporation business tax up to the date of dissolution or withdrawal.  For more information on the Corporation Business Tax, review the instructions to Form CT-1120 .
S CORPORATION ELECTION:  A corporation that elects S corporation status for federal income tax purposes must also file as an S corporation for Connecticut income tax purposes.  There is no separate election for Connecticut tax purposes.

COMPOSITE INCOME TAX FILING REQUIREMENTS:   An S corporation is required to file Form CT-1065/CT-1120SI, where it:

    • Is required to file federal Form 1102S, U.S. Income Tax Return for an S Corporation; and
    • Has any income, gain, loss, or deduction derived from or connected with sources within Connecticut.

(For information on the composite filing requirements for partnerships and other pass-through entities taxed as partnerships, visit our Partnership page.)

An S corporation is required to file Form CT-1065/CT-1120SI, Connecticut Composite Income Tax Return, and make a composite Connecticut income tax payment on behalf of each nonresident non-corporate shareholder or pass-through entity that is a shareholder where the shareholder’s pro rata share of the PE's income derived from or connected with Connecticut sources is $1,000 or more.  


For more information, please see IP 2006(22), Connecticut Income Tax Changes Affecting Pass-Through Entities.


BUSINESS ENTITY TAX There is an annual tax of $250 on each domestic or foreign entity (S corporation, limited liability company, including single member limited liability company , limited liability partnership, and limited partnership), where the entity is required to file an annual report with the Connecticut Secretary of the State. The tax is required to be paid to DRS by an entity on or before the fifteenth day of the fourth month following the close of each taxable year of the entity (April 15 for calendar year filers). (An entity’s taxable year is its taxable year for federal income tax purposes.)   Visit the Business Entity Tax Page for more information.