How to Register a DBA in Connecticut

If you plan to run your business under any name other than your own legal name, you need to register a DBA in Connecticut before you can legally operate. Known officially as a “trade name,” a DBA, short for “doing business as,” is a state-mandated filing governed by Connecticut General Statutes Section 35- 1. Whether you’re a first-time sole proprietor or an established LLC expanding under a new brand, this guide covers every step of the process, including the important law changes that took effect under Public Act 24-111 on January 1, 2025.

What is a DBA (trade name) in Connecticut?

In Connecticut, the term “trade name” is the legal equivalent of a DBA. It is any name a person or business uses to transact business that differs from their real legal name. For example, a sole proprietor named Maria Chen who wants to operate a bakery called “Harbor Sweets” cannot use that name publicly or professionally without first filing a Connecticut trade name certificate.

Critically, a trade name is not a business entity. It creates no separate legal structure, offers no liability protection, and does not grant exclusive ownership of that name even after you file it. Two businesses in two different Connecticut towns can legally hold the same trade name.

Who is required to register a DBA in Connecticut?

Connecticut law is clear: anyone conducting business under an assumed name must file a trade name certificate with the town clerk in the town where that business is primarily transacted. This applies to:

• Sole proprietors operating under any name other than their full legal name
• General partnerships where the business name omits the true last name of at least one partner
• LLCs and corporations wishing to operate under a name other than their Secretary of State–registered legal name
• Foreign business organizations with a Connecticut office or resident agent

When you don’t need to file

A trade name certificate is not required if your partnership name already contains the true surname of at least one partner, or if your LLC operates solely under the exact name registered with the Secretary of State.

Benefits and limitations of a Connecticut trade name

Filing a trade name gives your business a public-facing identity separate from your legal name. You can open bank accounts, sign contracts, issue invoices, and market your business under the DBA name. You can also register multiple DBAs under a single legal entity, useful for businesses running more than one brand or product line.

Connecticut DBA name rules: what you can and can’t use

Before you register a DBA in Connecticut, your chosen trade name must comply with state naming restrictions. Your name cannot:

• Misidentify your business type (e.g., using “bank” or “insurance” without the proper license)
• Duplicate a federally or state trademarked name
• Use words that imply government affiliation
• Be identical or confusingly similar to a trade name already registered in your town

How to check name availability

Connecticut is still building its statewide searchable trade name registry, expected to launch on business.ct.gov by January 1, 2026. Until then, check availability by contacting your local town clerk directly, searching Secretary of State records at business.ct.gov, and reviewing the USPTO database for any federal trademark conflicts. Some towns, like Stamford, offer an online trade name lookup; most others require a phone call or in-person visit.

How to register a DBA in Connecticut  step by step

The following steps reflect the updated process under Public Act 24 111, effective January 1, 2025.

Filing requirements by applicant type

Connecticut DBA filing costs and processing times

In-person filings are typically processed the same day. Mail filings vary; allow several business days depending on your town.

What to do after you register a DBA in Connecticut

• Open a business bank account under your trade name. Most financial institutions require a certified copy of your filed certificate
• Apply for an EIN at irs.gov. If you plan to hire employees or need one for banking or tax purposes, it’s free and takes minutes
• Update licenses and permits to reflect your trade name wherever required by your municipality or industry
• Refresh your marketing materials: website, signage, business cards, and invoices should all reflect the new name
• Consider a trademark search if you want brand protection that extends beyond Connecticut’s borders

2025 renewal, expiration, and cancellation rules (PA 24-111)

One of the biggest changes when you register a DBA in Connecticut under the new law is that trade names now have an expiration date. Under Public Act 24-111:

• Trade names filed on or after January 1, 2025, expire five years from the filing date, unless renewed
• Trade names filed before January 1, 2025, remain valid until December 31, 2029
• A renewal filing extends the registration for another five-year period
• An amendment filing allows you to update any information originally submitted
• A cancellation filing ends your trade name registration before its expiration date