Single-Member LLC in Illinois: Rules & Taxes (2026)

Fact-checked by the LegalGlass editorial team against primary sources · Published Aug 20, 2026 · Last updated Aug 20, 2026

Illinois permits a limited liability company with a single member. You create one by filing Form LLC-5.5, Articles of Organization, with the Illinois Secretary of State, and you keep it alive by filing Form LLC-50.1, the LLC Annual Report, every year. For federal tax, the IRS treats a single-member LLC as a disregarded entity by default.

Quick Answer

Allowed
Yes - Illinois recognizes one-member LLCs
Formation form
Form LLC-5.5, Articles of Organization
Agency
Illinois Secretary of State, Department of Business Services
Annual filing
Form LLC-50.1, LLC Annual Report
Federal tax default
Disregarded entity - Schedule C on Form 1040
EIN
$0 - free from the IRS
Registered agent
Required, with an Illinois street address

Can One Person Own an Illinois LLC?

Yes. The Illinois Limited Liability Company Act permits an LLC with one member, and the Illinois Secretary of State processes single-member filings on the same form and through the same channel as multi-member filings. Nothing on Form LLC-5.5 asks you to justify having a single owner, and the state does not charge a different fee or apply a different review standard. A one-member Illinois LLC has the same legal separation from its owner as a two-member LLC: the company holds its own assets, signs its own contracts, and is the party named in its own lawsuits.

The practical difference is federal, not state. A single-member LLC is treated differently by the IRS than a multi-member LLC, which is the single most important thing to understand before you file. See how to form an LLC in Illinois for the full formation walkthrough, and what an LLC is for the concept.

Filing Form LLC-5.5

The document that creates the company is Form LLC-5.5, Articles of Organization, filed with the Secretary of State's Department of Business Services. You can file it online through the Secretary of State's LLC application or submit the paper form. The Articles ask for the LLC name, the principal place of business, the registered agent and registered office, the purpose, and whether the company is member-managed or manager-managed. A single-member LLC is almost always member-managed, with the sole member listed as the manager or member.

Illinois also publishes a separate series-LLC version of the Articles for companies that want to create protected series. A single-member LLC that is not creating series should use the standard LLC-5.5. The Secretary of State sets the filing fee; confirm the current amount on the Illinois Secretary of State LLC page before you send payment, because Illinois publishes fees on the form itself. For the document itself, see Illinois Articles of Organization.

Naming a One-Member Illinois LLC

The company name must contain an LLC designator and must be distinguishable from other names already on the Secretary of State's records. Check availability with the Illinois business entity search before you file, and again immediately before submission - names are claimed in the order filings are accepted, not in the order searches are run. If you plan to trade under a different name, register it as an assumed name; see Illinois DBA filing. A DBA does not create a separate company and does not give you trademark rights.

Registered Agent Requirement

Every Illinois LLC must continuously maintain a registered agent with a registered office at a street address in Illinois. A post office box alone is not sufficient. As the sole member you may serve as your own agent if you have an Illinois street address and are generally available during business hours, but that address becomes part of the public record. Many single-member owners who work from home hire a commercial agent to keep their home address off the file. See Illinois registered agent requirements and the national registered agent overview.

Form LLC-50.1: The Annual Report

An Illinois LLC files Form LLC-50.1, the LLC Annual Report, each year with the Secretary of State. The report confirms the company's address, registered agent, and management information. Illinois runs an online annual report application, and the Secretary of State's instructions state that any penalties accrued as of the filing date must be paid together with the filing fee at the time the report is filed. Missing the report is the most common reason an otherwise healthy single-member LLC falls out of good standing, because there is no partner to notice the lapse. Details are in the Illinois annual report guide.

Federal Tax: Disregarded by Default

The IRS treats a domestic single-member LLC as a disregarded entity unless the owner elects corporate treatment. Disregarded means the company is ignored for income tax: the sole member reports the business income and expenses directly, normally on Schedule C (Form 1040), and pays self-employment tax on the net earnings. There is no separate federal income tax return for the LLC itself, and no Schedule K-1.

Disregarded status applies only to income tax. The IRS treats a single-member LLC as a separate entity for federal employment taxes and for certain excise taxes, which is why the company needs its own EIN if it has employees. Because no employer withholds tax from a member's draws, most single-member owners pay quarterly estimated tax. See the self-employment tax calculator and the business tax hub.

Electing S-Corp or C-Corp Treatment

A single-member LLC may elect to be taxed as a corporation, and from there as an S corporation, by filing the appropriate IRS election. That changes the federal return, adds payroll obligations, and does not change anything about the Illinois filing - the company still files LLC-5.5 and LLC-50.1 and is still an LLC under state law. Weigh the tradeoff in S-corp vs LLC before electing; the payroll and return-preparation cost is real and often exceeds the savings for a small single-member operation.

Illinois State Tax

A single-member LLC that is disregarded federally flows its income onto the owner's Illinois individual return. Illinois also imposes a personal property replacement tax on some business entities, and businesses selling taxable goods must register with the Illinois Department of Revenue for retailers' occupation tax. Registration and rate details belong to the Department of Revenue, not the Secretary of State - keep the two agencies separate in your records. See Illinois LLC tax filing for the state return picture.

Keeping Liability Protection Intact

Single-member LLCs draw more piercing-the-veil scrutiny than multi-member ones, because there is no second owner to enforce discipline. Three habits do most of the work: keep a dedicated business bank account and never pay personal expenses from it; sign contracts in the LLC's name and in your capacity as member or manager, not in your personal name; and adopt a written Illinois operating agreement even though Illinois does not file one. A single-member operating agreement documents that the company is a real entity with its own governance, and banks and lenders routinely ask for it.

Licenses, Employees, and Later Steps

Forming the LLC does not license the business. Illinois regulates many activities at the state level and most municipalities license businesses locally; see Illinois business licenses and the national business license guide. If you expand into another state you will register there as a foreign LLC - see foreign LLC in Illinois. If you eventually wind the company down, follow how to dissolve an LLC in Illinois rather than simply abandoning the annual report, which leaves the entity delinquent instead of closed.

Frequently Asked Questions

Can an Illinois LLC have only one member?

Yes. The Illinois Limited Liability Company Act allows an LLC with a single member, and the Illinois Secretary of State uses the same Form LLC-5.5 Articles of Organization for one-member and multi-member companies. There is no extra step, no different form, and no separate approval process for a single-member Illinois LLC.

How is a single-member LLC in Illinois taxed?

By default the IRS treats a domestic single-member LLC as a disregarded entity. The sole member reports the business income and expenses on Schedule C of the Form 1040 and pays self-employment tax on the net earnings. The LLC files no separate federal income tax return unless the owner elects corporate or S corporation treatment.

What annual filing does an Illinois single-member LLC owe?

Illinois LLCs file Form LLC-50.1, the LLC Annual Report, with the Secretary of State each year. The report confirms the address, registered agent, and management information. The Secretary of State's instructions state that any penalties accrued as of the filing date must be paid along with the filing fee when the report is submitted.

Does a single-member Illinois LLC need an EIN?

Not always for income tax, because a disregarded single-member LLC can often use the owner's Social Security number. It does need an EIN if it has employees, owes certain excise taxes, or elects corporate treatment. Most banks require an EIN to open a business account, and the IRS issues EINs free of charge.

Can I be my own registered agent in Illinois?

Yes, if you have a street address in Illinois and are generally available during business hours to accept service of process. A post office box alone does not qualify. Because the registered office address is public, many single-member owners who work from home use a commercial registered agent instead.

Does a single-member LLC still protect my personal assets?

Yes, an Illinois single-member LLC is a separate legal entity. Protection depends on keeping it separate in practice: a dedicated business bank account, contracts signed in the company's name, and a written operating agreement. Mixing personal and business funds is the most common way owners undermine that protection.

Related

Sources

  1. Illinois Secretary of State - Limited Liability Companies (agency, filing channel, fees).
  2. Illinois Secretary of State - Form LLC-5.5, Articles of Organization.
  3. Illinois Secretary of State - LLC Publications and Forms.
  4. Illinois Secretary of State - Form LLC-50.1, LLC Annual Report.
  5. Illinois Secretary of State - File an Annual Report.
  6. Illinois Secretary of State - Information for Filing an LLC Annual Report Online (penalties due with the filing fee).
  7. Illinois Secretary of State - LLC Articles of Organization (online filing).
  8. Illinois Department of Revenue - Illinois Department of Revenue, state tax registration and retailers' occupation tax (linked in the state tax section above).
  9. IRS - Single Member Limited Liability Companies (disregarded entity; employment and excise tax exception).
  10. IRS - Limited Liability Company (LLC) (federal classification).
  11. IRS - About Schedule C (Form 1040).
  12. IRS - Self-Employment Tax.
  13. IRS - Get an Employer Identification Number (free EIN).
  14. IRS - Estimated Taxes.

LegalGlass provides general information for educational purposes and is not legal advice, is not a law firm, and is not a substitute for advice from a licensed attorney or tax professional. Laws, fees, and thresholds change; verify current amounts with the Illinois Secretary of State and the Illinois Department of Revenue before acting.