Start a Connecticut LLC: Step-by-Step Guide

Your LLC name has to be distinguishable from every other business name already registered in Connecticut. That is a legal standard, not a matter of taste: a name that differs only by punctuation, spacing, or a filler word like "the" may still be rejected as too similar. The Secretary of the State reviews all names on record, including corporations, limited partnerships, and other entity types, not only LLCs.

Run your proposed name and its close variants through the Connecticut online business search. Look for anything that sounds or reads like your choice. If a conflict exists, the state may reject your Certificate of Organization, which delays everything.

Name requirements

• Must include "limited liability company," "L.L.C.," or "LLC"; "Limited" may be shortened to "Ltd." and "Company" to "Co."
• Must be distinguishable from the names on the Secretary of the State's records. When the state compares names, entity designators like "Inc.," "Ltd.," or "LLC" are not taken into account.
• Cannot contain language implying a purpose the LLC isn't authorized to pursue.

Optional: reserve the name

If you are not ready to file but want to hold a name, Connecticut lets you reserve an available name for 120 days for $60. A reservation does not create the LLC; it just locks the name while you handle the rest.

Trade names (DBAs) are different in Connecticut

If you plan to operate under a name other than your LLC's legal name, Connecticut handles that at the local level. Trade names (also called fictitious or assumed names) are filed with the town clerk in the town where you do business, not with the Secretary of the State and not with the county. Registrations run for five years and each town sets its own process. This is entirely separate from forming the LLC.

Before you file, you need a registered agent chosen and willing to serve, because the agent's name and addresses go into the Certificate of Organization and the agent signs it to accept the appointment.

Connecticut requires every LLC to keep a registered agent for the life of the company. The agent receives lawsuits, subpoenas, regulatory notices, and official state mail on the LLC's behalf.

Who can serve

• You: If you are a Connecticut resident, you can serve as a member or manager of the LLC. You list a business address (or "none"), a Connecticut residence address that isn't a P.O. box, and a Connecticut mailing address.
• Another individual: Any Connecticut resident, such as a co-owner, an employee, or a Connecticut attorney, giving the same addresses.
• A business entity: A Connecticut corporation, LLC, LLP, or statutory trust, or one from another state that is registered in Connecticut. Commercial registered agent services fall here, and they keep their professional address on the public record instead of yours.

The LLC itself may not be its own agent, as the state's form says plainly.

Why it matters

The Certificate of Organization is a public record, so an individual agent's information becomes findable. Many owners choose a commercial service specifically to keep their home address private and to have papers received even when they travel or work irregular hours. Changing agents later costs $50.

The Certificate of Organization is the filing that creates your LLC in Connecticut's records. You file it online through the Business One Stop portal at business.ct.gov with a Business.CT.gov account, or mail the paper form with a check payable to "Secretary of the State." The state fee is $120 either way, and it includes the appointment of your registered agent.

Connecticut publishes no standard turnaround, but the Secretary of the State says most filings made on Business.CT.gov are automatically accepted. A $50 expedite is available only for online filings, offered at the end of the process. Once accepted, the LLC appears in the public business record and your filed documents become available.

What goes into the Certificate

• LLC name with the required designator ("LLC," "L.L.C.," or the full phrase).
• Principal office address: a street address, not a P.O. box, plus a mailing address.
• Registered agent name and addresses, with the agent's signature accepting the appointment.
• At least one member or manager: name, title, business address, and residence address.
• Business email address and six-digit NAICS code: both required since January 1, 2025.
• Organizer signature, under penalty of false statement. The LLC can't be its own organizer.

What you do not have to include

You do not list members' ownership percentages, describe the business in detail, or disclose any financials. The Certificate is a short formation document. Your internal details live in the operating agreement, which stays private.

An operating agreement is your LLC's internal rulebook. Connecticut does not require you to file it and it never becomes public, but you should have one before you start doing business, add members, or open accounts.

What a solid operating agreement covers

• Ownership: member names, ownership percentages, and how interests are held.
• Capital contributions: what each member put in and any obligation to contribute more later.
• Profit and loss allocation: how gains and losses are split, usually, but not necessarily, in line with ownership.
• Distributions: when and how cash is paid out, and in what order.
• Management: who runs the company day to day and which decisions need a member vote.
• Voting: whether votes are weighted by ownership or counted per member.
• Transfers: what happens when a member wants to sell or leave: rights of first refusal, approval requirements.
• Dissolution: how and when the company can be wound up and how assets are divided.

For single-member LLCs, the agreement reinforces that the company is a genuine separate entity: courts weigh that when someone challenges the liability shield, and banks often ask for it. For multi-member LLCs it is essential; without it, Chapter 613a's default rules govern, and they rarely match what the members had in mind.

An Employer Identification Number is the nine-digit federal tax ID the IRS provides free of charge. It works like a Social Security number for the business. You use it on tax filings, to open bank accounts, and to hire employees.

When you need one

• Your LLC has more than one member (a partnership return requires an EIN).
• You plan to hire employees.
• You want a business bank account (most banks require an EIN).
• You have elected S-corp or C-corp tax treatment.

A single-member LLC with no employees can technically use the owner's Social Security number, but most owners get an EIN anyway to keep the SSN off business paperwork and to simplify banking.

How to apply

Go to IRS.gov and work through the online EIN Assistant. It runs about ten minutes, and since the IRS assigns the number on the spot, you can put it to use that same day. You need a U.S. Social Security number or ITIN to apply online; applicants without one file Form SS-4 by fax or mail. There is no IRS fee. When Mainstay Filing forms your LLC, we apply for the EIN for you once the Certificate is accepted.

Keeping the LLC's finances separate is not optional. It is what preserves the liability shield. If you pay personal expenses from the business account or run business income through your personal account, a court can disregard the LLC and hold you personally liable.

What most banks want to open an LLC account

• Your filed Certificate of Organization from the Secretary of the State.
• Your IRS EIN confirmation.
• Your operating agreement (many banks ask for it: have it ready).
• Government-issued ID for every authorized signer.

Connecticut community banks and credit unions are often more flexible with brand-new LLCs than large national chains, and several online business banks can open an account without a branch visit. Before you settle on one, weigh the monthly fees, the caps on transactions, and any minimum-balance rules.

Most of the compliance work is front-loaded into formation. After that, it is mainly one annual filing plus attention to any change in your agent or address.

Annual report

Starting the year after you form, file between January 1 and March 31 each year, online only, through Business.CT.gov. The fee is $80, and the state emails a reminder about a month ahead. It updates your registered agent, addresses, and member or manager details. It is not a financial disclosure. There's no late fee, but you can't get a Certificate of Legal Existence while it's overdue, and an LLC more than a year in default can be dissolved by forfeiture if it doesn't file within three months of the state's emailed notice.

Registered agent and address changes

If your registered agent changes address, resigns, or you switch agents, file the update with the Secretary of the State promptly. A stale agent address leaves the LLC technically non-compliant even when everything else is current.

Taxes

Federal treatment follows your structure: Schedule C for single-member, Form 1065 for multi-member, Form 1120-S for an S-corp election. Connecticut taxes pass-through income at the individual level; its Pass-Through Entity Tax has been elective since January 1, 2024, and the old Business Entity Tax no longer exists. If you sell taxable goods or services, register for sales and use tax with the Department of Revenue Services.

Licenses and permits

Connecticut issues no single general business license, but many professions require state licensure, and some towns have their own permit requirements. These run on their own cycles, separate from your LLC registration with the Secretary of the State.