How to Apply for an EIN in Connecticut

The EIN step itself

One federal form, one agency, the same options wherever the business sits: online, fax, mail, or the international phone line. The method decides the timeline, not the state. Every method and what it actually takes covers that in full, and it applies to Connecticut unchanged.

What Connecticut needs first

Form your entity with the Connecticut Secretary of the State before applying. The IRS asks for the legal name and formation date exactly as the state recorded them, and a mismatch is one of the common causes of a rejected application.

Connecticut assigns its own business ID. It identifies your company in state records and is not a tax ID. It cannot be used where an EIN is asked for, and the IRS has no record of it.

What Connecticut requires once you have the EIN

• Register with the Connecticut Department of Revenue Services through myconneCT before your first taxable sale or first payroll. The registration asks for the EIN and opens sales and use tax and withholding in one application.
• File the LLC annual report with the Secretary of the State between January 1 and March 31 every year, starting the calendar year after formation. It is filed on business.ct.gov under the business ID, not the EIN.

What is actually different about Connecticut

• Connecticut's annual report window is fixed for every LLC regardless of formation date: January 1 to March 31. Most states tie the due date to the formation anniversary, so an LLC formed in Connecticut in December owes its first report within about three months of existing.
• Connecticut's pass-through entity tax was mandatory for LLCs taxed as partnerships or S corporations from 2018 through 2023 and became elective for tax years beginning in 2024. Whether to elect it is now a yearly decision that depends on the members' own returns, and it is made with the entity return rather than on the SS-4.
• business.ct.gov puts the Secretary of the State filing, the Department of Revenue Services registration and the Department of Labor employer registration behind one login, which is why Connecticut owners usually finish state setup in a single session once the EIN exists.