How to Start a C-Corp in Connecticut (Quick Answer)
To start a C-corp in Connecticut, file a Certificate of Incorporation with the Connecticut Secretary of the State, name a registered agent, and pay the $250 filing fee. Once the state accepts it, your corporation legally exists.
After that, you adopt bylaws, appoint directors and officers, issue stock, and get an EIN from the IRS. Connecticut is one of the pricier states to run a corporation in, and the filing fee itself rises if you authorize a lot of shares.
| Filing document | Certificate of Incorporation |
| Where to file | Connecticut Secretary of the State |
| Filing fee | $250, which rises if you authorize more than 20,000 shares (Connecticut adds an organization tax based on authorized shares) |
| Registered agent | Required, with a physical Connecticut street address |
| EIN | Required, free from the IRS (Form SS-4 by phone, fax, or mail if you have no SSN or ITIN) |
| Annual report | $150, filed with the Secretary of the State each year |
| Corporation Business Tax | 7.5% on net income, plus a 10% surtax for companies with $100 million or more in annual gross income |
| Foreign owner (25% or more) | File Form 5472 with Form 1120 every year, or face a $25,000 minimum penalty |
First-year cost: $250 to file if you keep authorized shares at or below 20,000, plus a registered-agent service if you use one, commonly $50 to $150 a year. Authorizing more shares raises the filing fee.
Connecticut costs more to form in and maintain than many states. The $250 filing fee climbs when you authorize more than 20,000 shares, because the state adds an organization tax tied to your authorized shares.
Ongoing, you file a $150 annual report and pay the 7.5% Corporation Business Tax, with a 10% surtax on top for the largest companies.
TL;DR
- Connecticut is a higher-cost state: $250 to form (more if you authorize over 20,000 shares), a $150 annual report, and a 7.5% Corporation Business Tax.
- Step 1, name: pick a unique name with a corporate designator (Inc., Incorporated, Corporation, or Corp.) and check it with the Secretary of the State.
- Step 2, registered agent: name one with a physical Connecticut street address.
- Step 3, Certificate of Incorporation: file with the Secretary of the State for $250, more if you authorize over 20,000 shares.
- Step 4, bylaws: adopt internal bylaws and keep them with your records.
- Step 5, directors and officers: appoint the board and officers and hold an organizational meeting.
- Step 6, issue stock: authorize and issue shares, keep a stock ledger, and file the 83(b) election within 30 days if your shares vest.
- Step 7, EIN: get a free EIN from the IRS, by Form SS-4 if you have no SSN or ITIN.
- Foreign owner (25% or more): file Form 5472 with Form 1120 every year, or risk a $25,000 penalty.
- Ongoing: a $150 annual report, plus the 7.5% Corporation Business Tax (with a 10% surtax for companies over $100 million in gross income).
Why Form a C-Corp in Connecticut?
Connecticut offers access to the wider New York and Boston corridor with a skilled workforce in finance, insurance, and manufacturing.
- Location between New York and Boston, with strong finance and insurance sectors.
- A deep professional workforce.
- Online filing through the Secretary of the State's business portal.
Weigh the cost first. If you plan to raise venture capital, investors will most likely want a Delaware C-corp. Connecticut's filing fee, annual report, and 7.5% tax with a surtax make it a higher-cost home, so it fits businesses that genuinely operate there.
Step 1: Choose and Reserve Your Corporate Name
- Include a corporate designator such as "Inc.", "Incorporated", "Corporation", or "Corp."
- Search the Secretary of the State's business database to confirm the name is available and different from existing entities.
- Connecticut lets you reserve a name for 120 days for a fee if you are not ready to file.
Step 2: Appoint a Connecticut Registered Agent
Every Connecticut corporation must name a registered agent with a physical Connecticut street address, available during business hours to receive legal and state documents.
- The agent can be a person or a company, but needs a real Connecticut address, not a PO box.
- The address is public record, so many owners use a commercial service.
- A commercial agent commonly costs $50 to $150 a year.
Step 3: File Your Certificate of Incorporation
The Certificate of Incorporation is the filing that legally creates your corporation. You file it with the Connecticut Secretary of the State.
- It lists the corporate name, registered agent, and the number of shares the corporation is authorized to issue.
- The fee starts at $250, and it rises if you authorize more than 20,000 shares, because Connecticut adds an organization tax tied to authorized shares.
- Once the state accepts it, your corporation exists and its compliance calendar begins.
Step 4: Adopt Corporate Bylaws
Bylaws are the internal rulebook for how the corporation is run. They are not filed with the state, but a corporation is expected to have them, and banks and investors often ask to see them.
- They set out how directors and officers are elected, how meetings and votes work, and how shares are handled.
- They stay with your records, not with the Secretary of the State.
- Skipping them can weaken the separation between you and the corporation that liability protection depends on.
Step 5: Appoint Directors and Hold the Organizational Meeting
A corporation is run by a board of directors, who appoint the officers that handle day-to-day work. Right after formation, the incorporator or initial directors hold an organizational meeting, or sign a written consent in place of one.
- Appoint the initial board and elect officers (usually at least a president, secretary, and treasurer; one person can hold several roles).
- Adopt the bylaws and authorize the issuance of stock.
- Keep signed minutes or the written consent with your records.
Step 6: Authorize and Issue Stock
Issuing stock is how founders get their ownership, and it is easy to rush. The board authorizes shares, then the corporation issues them to the founders and any early shareholders.
- Issue shares to each founder and record what they paid (cash, property, or services).
- Keep a stock ledger, a running record of who owns how many shares.
- Watch your authorized share count. In Connecticut, authorizing more than 20,000 shares raises your filing fee through the organization tax.
The 83(b) election, and its 30-day deadline: if your founder shares vest over time, you generally have 30 days from the grant date to file an 83(b) election with the IRS.
It lets you be taxed on the small value at grant instead of the higher value as the stock vests. The 30-day window cannot be extended, and missing it can be expensive.
Step 7: Get an EIN, Even Without an SSN
An EIN is your corporation's federal tax ID, needed to file taxes, run payroll, and open a bank account. It is free from the IRS.
- With an SSN or ITIN, apply online and get the EIN in minutes.
- Without an SSN or ITIN, apply on Form SS-4 by phone, fax, or mail.
- The EIN is always free; you never pay the IRS for one.
Open a US Business Bank Account
Once you have the EIN, open a dedicated business bank account before money moves through the corporation.
- Keeping corporate and personal funds separate helps protect the liability shield; commingling them is a common reason courts pierce it.
- Banks usually ask for the filed Certificate of Incorporation, the EIN letter, and often the bylaws or a board resolution.
- A separate account also makes bookkeeping and the corporate tax return simpler.
If Your Connecticut C-Corp Is Foreign-Owned
A Connecticut C-corp that is 25% or more owned by a non-US person has an extra federal filing that many international founders miss.
- The corporation files Form 5472 with its annual Form 1120 to report transactions with the foreign owner, such as money put in or paid out for services.
- It is required every year there are reportable transactions, even with little or no profit.
- The penalty is steep: a missed or late Form 5472 starts at $25,000 per form, per year.
Handle Connecticut's Ongoing Compliance
Two obligations run every year: the annual report and the Corporation Business Tax.
The $150 Annual Report
- Every Connecticut corporation files an annual report with the Secretary of the State for $150.
- It confirms your officers, directors, registered agent, and address.
- Missing it can put the corporation out of good standing and eventually lead to administrative dissolution.
The Corporation Business Tax
- Connecticut charges a 7.5% Corporation Business Tax on net income.
- A 10% surtax applies to companies with $100 million or more in annual gross income, so most small corporations pay just the 7.5%.
- Federally, the corporation files Form 1120 and pays 21% corporate tax, due the 15th day of the 4th month after year-end.
How Much Does It Cost to Start a C-Corp in Connecticut?
| What you pay | Amount | When |
|---|---|---|
| Certificate of Incorporation filing | $250 (rises if you authorize over 20,000 shares) | One time, at formation |
| Registered-agent service (optional) | ~$50 to $150 a year | Yearly, if you use one |
| Annual report | $150 | Yearly |
| Corporation Business Tax | 7.5% of net income (plus a 10% surtax over $100M gross income) | Yearly |
| Federal corporate tax | 21% of profits | Yearly, with Form 1120 |
How Long Does It Take to Start a C-Corp in Connecticut?
- Online filings through the Secretary of the State are usually processed within a few business days.
- The EIN follows: minutes online with an SSN or ITIN, or same day to several weeks by Form SS-4 without one.
- Bylaws, the organizational meeting, and issuing stock happen right after the state approves the filing.
Common Mistakes to Avoid
- Authorizing more shares than you need, which raises the Connecticut filing fee through the organization tax.
- Missing the annual report, which can put the corporation out of good standing.
- Missing the 30-day 83(b) deadline on vesting founder stock.
- Overlooking Form 5472 if the corporation is 25% or more foreign-owned.
- Using a PO box for the registered agent, which Connecticut does not accept.
How FinStackk Helps
FinStackk is an accounting and tax compliance platform for U.S. businesses, taking you from incorporation through ongoing accounting, tax, and compliance in one place.
We handle Connecticut C-corp formation, from the Certificate of Incorporation to the EIN, through Fin-Start, including the Connecticut registered agent.
Once the corporation exists, Fin-Tax keeps the federal Form 1120 deadline, estimated taxes, and the Connecticut Corporation Business Tax on a proactive calendar. Complyy tracks the $150 annual report and your registered-agent renewal. Book a free demo to see them in action.
FAQ
How much does it cost to start a C-corp in Connecticut?
It costs $250 to file the Certificate of Incorporation if you authorize 20,000 shares or fewer. Authorizing more raises the fee through Connecticut's organization tax on authorized shares. Add a registered-agent service if you use one, and going forward budget for the $150 annual report and the 7.5% Corporation Business Tax.
What is Connecticut's Corporation Business Tax?
Connecticut charges a 7.5% Corporation Business Tax on a C-corp's net income. A 10% surtax applies on top for companies with $100 million or more in annual gross income, so most small corporations pay just the 7.5%. This is separate from the 21% federal corporate tax on Form 1120.
Why does the Connecticut filing fee change with share count?
Connecticut adds an organization tax based on the number of shares you authorize. If you authorize 20,000 shares or fewer, the filing runs the base $250. Authorize more, and the organization tax raises the total, so it pays to authorize only the shares you need at formation.
Is it better to form a C-corp or an LLC in Connecticut?
An LLC is simpler and taxed once, which suits many small businesses. A C-corp makes sense if you plan to raise venture capital, keep earnings in the business, or want multiple classes of stock. A C-corp is taxed twice, once at the corporate level and again on dividends, on top of Connecticut's Corporation Business Tax.
Should I form my C-corp in Connecticut or Delaware?
If you plan to raise venture capital, Delaware is what investors expect. If you will operate in Connecticut and not raise venture money, forming in Connecticut avoids registering and paying in two states, since a Delaware corporation doing business in Connecticut still has to register and pay here. Choose based on where you operate and whether you will raise money.
Can a non-US resident start a Connecticut C-corp?
Yes. Connecticut sets no citizenship or residency requirement to own a corporation. You will need a Connecticut registered agent and an EIN, which you apply for on Form SS-4 by phone, fax, or mail without an SSN. If a non-US person owns 25% or more, the corporation also files Form 5472 with its Form 1120 every year, with a $25,000 minimum penalty for missing it.