Sole Proprietorship in Montana: How to Start (2026)

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

A Montana sole proprietorship requires no formation filing with the state - you are a sole proprietor the moment you start doing business for yourself. The one Secretary of State step is conditional: if you do business under a name other than your own, you must register an assumed business name, which costs $20 and is renewed every five years.

Quick Answer

Formation filing: None - no state registration to become a sole proprietor
Assumed business name: $20, required only if not using your own name
ABN renewal: Every five years
Agency: Montana Secretary of State, Business Services Division
Veterans and active military: Initial new-business filing fees, including the ABN, are waived
Federal tax: Schedule C (Form 1040) plus self-employment tax
Liability: Unlimited - no separation between you and the business

No Registration Needed to Be a Sole Proprietor

Montana does not create sole proprietorships; it simply recognizes them. The Montana Secretary of State states that if you plan to start a sole proprietorship and you are not planning to do business under your own name, you must register an assumed business name - and that otherwise, no registration is required. There is no articles filing, no charter, and no annual report for the sole proprietorship itself. That is the structure's main advantage and, as covered below, the source of its main drawback.

A sole proprietorship is not a separate legal entity. You and the business are the same person in the eyes of the law. Contracts are your contracts, debts are your debts, and a judgment against the business reaches your personal assets. If that risk matters for your activity, compare forming a Montana LLC instead, and read what an LLC is.

Registering an Assumed Business Name

If you want to trade as anything other than your own legal name, you register an assumed business name (ABN) with the Secretary of State. The fee is $20, and the registration must be renewed every five years. The Secretary of State has also eliminated the initial filing fee for new business filings - including a new assumed business name - for veterans and active-duty military members.

Registering an ABN does not create an entity, does not limit your liability, and does not give you exclusive rights to the name in the trademark sense. It puts the public on notice of who is behind the trade name. Montana files ABNs online through the Secretary of State's business portal, and the Business Services Division publishes a fee sheet listing every filing fee it charges. See Montana DBA filing for the mechanics and what a DBA is for the general concept.

Checking the Name First

Before you register, search the Secretary of State's records so your assumed name is not already taken by another filer. Use the Montana business entity search. A clear search result at the state level is not a trademark clearance - state registration and trademark rights are separate systems. If the name is central to your business, read the trademark hub and consider a federal application before you invest in signage and packaging.

Do You Need an EIN?

A sole proprietor with no employees can generally use a Social Security number for federal tax purposes, so an EIN is not automatically required. You do need one if you hire employees, file certain excise or pension returns, or operate as an employer for withholding purposes. Many banks also ask for an EIN before opening a business account under an assumed name. The IRS issues EINs at no cost, and no third party needs to be paid to obtain one.

Federal Tax for a Montana Sole Proprietor

A sole proprietor reports business income and expenses on Schedule C (Form 1040) and pays self-employment tax on the net earnings, which covers the Social Security and Medicare contributions an employer would otherwise share. Because nobody withholds tax from your own draws, most sole proprietors also make quarterly estimated tax payments. Set aside a fixed percentage of every deposit from the start; the first-year underpayment surprise is the most common cash-flow problem new proprietors report. Try the self-employment tax calculator and see the business tax hub.

Montana State Tax and Registration

State tax obligations are administered by the Montana Department of Revenue, not the Secretary of State. Which registrations apply depends on what you sell and whether you have employees - for example, withholding accounts for employers and any activity-specific taxes the Department collects. Check the Department of Revenue's tax listing for your activity before you begin trading, and keep Department of Revenue accounts separate from Secretary of State filings in your records. See Montana business tax filing for the entity-level picture.

Licenses and Local Permits

Being a sole proprietor does not exempt you from licensing. Montana regulates many occupations at the state level, and cities and counties may require their own local registrations or permits. Licensing is driven by what you do and where you do it, not by your entity type, so a sole proprietor and an LLC doing the same work generally need the same licenses. Start with the business license overview and confirm local rules with your city or county clerk.

The Liability Trade-Off

The single most important thing to understand about a Montana sole proprietorship is that it provides no liability shield. If the business is sued or cannot pay a debt, your personal savings, vehicle, and home equity are exposed. Insurance helps but has limits and exclusions. For low-risk side work with few contracts, a sole proprietorship is often reasonable; for anything with employees, physical premises, meaningful contracts, or professional exposure, the cost of a Montana LLC is usually small relative to the protection. Montana LLC costs are set out in Montana LLC cost.

Converting to an LLC Later

Nothing locks you into a sole proprietorship. Owners commonly start as sole proprietors and form an LLC once revenue or risk grows. The conversion is practical rather than legal: file the Montana formation document, appoint a Montana registered agent, get an EIN for the LLC, open a new bank account, move contracts and licenses over, and adopt a Montana operating agreement. From then on the LLC must file the state's annual report to stay in good standing. Broader guidance is in how to start a business in Montana.

Records to Keep From Day One

Sole proprietors have the fewest formalities and therefore the weakest paper trail, which is what causes trouble at tax time. Open a separate bank account even though the law does not require one, keep receipts for every deduction you plan to claim, log business mileage contemporaneously, and keep copies of your ABN registration and any licenses. If you later form an LLC or sell the business, clean records are what make the transition provable. The IRS expects a sole proprietor to substantiate deductions the same way any business must.

Frequently Asked Questions

Do I have to register a sole proprietorship in Montana?

No. The Montana Secretary of State states that no registration is required unless you plan to do business under a name other than your own. In that case you must register an assumed business name. There is no articles filing, charter, or annual report for the sole proprietorship itself.

How much does a Montana assumed business name cost?

Registration of an assumed business name is $20 and must be renewed every five years. The Secretary of State has waived the initial filing fee for new business filings, including a new assumed business name, for veterans and active-duty military members. The fee is listed on the Business Services fee sheet.

Does a Montana sole proprietor need an EIN?

Not always. A sole proprietor with no employees can generally use a Social Security number for federal tax purposes. An EIN is required if you hire employees or file certain excise or pension returns, and many banks require one to open an account under an assumed name. The IRS issues EINs free.

How is a Montana sole proprietorship taxed?

The owner reports business income and expenses on Schedule C of Form 1040 and pays self-employment tax on the net earnings. Because no employer withholds tax, most sole proprietors make quarterly estimated tax payments. State tax obligations are handled separately by the Montana Department of Revenue.

Does a sole proprietorship protect my personal assets in Montana?

No. A sole proprietorship is not a separate legal entity, so there is no liability shield. Business debts and judgments reach your personal assets, including savings and home equity. Owners who want separation form a Montana LLC or corporation instead, which the Secretary of State does register.

Can I convert a Montana sole proprietorship into an LLC?

Yes. There is no legal conversion filing for a sole proprietorship; you simply form the LLC, appoint a registered agent, obtain an EIN, open a new bank account, and move contracts and licenses to the LLC. From then on the LLC files the state annual report to stay in good standing.

Sources

Montana Secretary of State - Business Structures (no registration unless using a name other than your own; $20 assumed business name; five-year renewal).
Montana Secretary of State - Business Services Filing Fees.
Montana Secretary of State - Business Filing Fee Schedule (PDF).
Montana Secretary of State - Business Services Division.
Montana Secretary of State - New business filing fees eliminated for veterans and active-duty military.
Montana Secretary of State - Business Forms.
Montana Department of Revenue - Taxes (state tax registration and administration).
IRS - Sole Proprietorships.
IRS - About Schedule C (Form 1040).
IRS - Self-Employment Tax.
IRS - Estimated Taxes.
IRS - Get an Employer Identification Number (free EIN).
IRS - Employer ID Numbers (when an EIN is required).

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 Montana Secretary of State and the Montana Department of Revenue before acting.