The legal structure of a business is the ownership and liability framework it operates under, and in the United States that framework is almost always one of four forms: a sole proprietorship, a partnership, a limited liability company (LLC), or a corporation. The structure you choose decides who owns the business, who is personally on the hook for its debts, how it is taxed, and how much paperwork the state expects from you each year. The practical differences are large. A sole proprietor can lose their home over a business debt. An LLC member usually cannot.
Sole Proprietorship
A freelance graphic designer who starts taking on clients without filing any formation paperwork is operating as a sole proprietor by default. There is no legal separation between the designer and the business. Every dollar earned belongs to the designer personally, and every debt the business owes is the designer’s personal obligation. If a client sues over a finished logo, the lawsuit targets the designer individually, and a judgment can reach personal savings, a car, and home equity.
This structure requires no state registration beyond any local permits or licenses the work demands. The designer reports all business income on their personal tax return and pays self-employment tax on the net profit, covering Social Security and Medicare. There are no annual reports to file with the state and no operating agreement to draft. The simplicity is the draw. The cost is unlimited personal exposure to every risk the business generates.
Partnerships
General Partnership
Two management consultants who agree to split revenue and expenses equally while serving clients together have formed a general partnership. A written agreement isn’t legally required — a handshake and shared profits can be enough, though operating without one is asking for trouble. Each partner acts as an agent for the other, so one consultant can sign a contract that legally binds both of them.
The financial exposure goes further than most people expect. Partners in a general partnership face joint and several liability. A creditor who wins a judgment against the partnership can collect the entire amount from whichever partner has the money. If one consultant is broke and the other owns a home, the creditor can pursue the homeowner for the full debt, not just half of it. The partner who pays more than their share can try to recover the difference from the other partner, but if that partner can’t pay, the loss stays where it landed.
Limited Partnership
A real estate developer who needs investor capital but wants to keep full control of a project might form a limited partnership. This structure has two tiers of participants. At least one general partner runs the operation and carries unlimited personal liability. One or more limited partners invest money but stay out of daily management, and their financial risk is capped at whatever they put in. If the development fails, limited partners lose their investment but nothing beyond it.
The trade-off is real. Limited partners who start making management decisions risk losing their liability protection, and a court can reclassify a limited partner as a general partner if that person was effectively running the business. The structure shows up often in real estate, oil and gas ventures, and private equity funds where passive investors want returns without operational risk.
Limited Liability Company
A property management company overseeing a portfolio of rental units is a natural fit for the LLC structure. The company itself, not its owners, signs the leases, hires maintenance contractors, and holds title to the properties. If a tenant slips on an icy walkway and sues, the lawsuit targets the LLC. The members’ personal bank accounts and homes generally sit behind a legal wall the tenant cannot reach.
LLCs achieve this by creating a separate legal person that can own property, enter contracts, and take on debt independently of the people who formed it. Members hold ownership interests rather than stock, and the internal rules live in an operating agreement rather than corporate bylaws. That operating agreement typically covers how profits and losses are divided, what happens when a member wants to leave, who has authority to sign contracts, how disputes are resolved, and how the company winds down if it dissolves. Skipping the operating agreement, which plenty of small LLCs do, means the state’s default rules fill in every gap, and those defaults rarely match what the members actually intended.
The IRS does not tax LLCs directly. A single-member LLC is treated as a disregarded entity, so the owner reports business income on their personal return just like a sole proprietor. A multi-member LLC is taxed as a partnership by default, with profits passing through to each member’s individual return. Either type can elect to be taxed as a corporation instead by filing Form 8832 with the IRS.1Internal Revenue Service. Limited Liability Company (LLC)
Corporations
C Corporation
A technology startup seeking venture capital almost always organizes as a C corporation. This structure lets the company issue multiple classes of stock: preferred shares with special voting rights or liquidation preferences for investors, and common shares for founders and employees. Investors expect this because it gives them contractual protections that LLCs and S corporations cannot easily replicate.
The governance is layered and formal. Shareholders own the company but do not manage it. They elect a board of directors, which sets long-term strategy and oversees major decisions. The board appoints officers, typically a CEO, CFO, and secretary, who handle daily operations. This separation of ownership from control is the defining feature of the corporate form, and it requires documentation to maintain: formal bylaws, recorded board minutes, shareholder resolutions, and annual meetings. Letting those formalities slide can undermine the liability protection the structure provides.
The tax cost is straightforward but significant. The corporation pays a flat 21 percent federal tax on its profits.2Office of the Law Revision Counsel. 26 USC 11 – Tax Imposed When those after-tax profits are distributed to shareholders as dividends, the shareholders pay tax again on the same money.3Office of the Law Revision Counsel. 26 USC 301 – Distributions of Property This double taxation is the price of the C corporation’s flexibility with stock classes and unlimited shareholders.
S Corporation
A family-owned grocery store that wants corporate liability protection without double taxation might elect S corporation status. The S corp is not a separate type of entity. It is a tax election that an eligible corporation makes with the IRS, and profits pass through to the shareholders’ personal tax returns to be taxed only once, similar to a partnership.
The eligibility rules are strict. The corporation cannot have more than 100 shareholders, all shareholders must be U.S. individuals or certain qualifying trusts and estates, and the company can issue only one class of stock.4Office of the Law Revision Counsel. 26 USC 1361 – S Corporation Defined That single-class-of-stock rule is what keeps venture-backed startups away from the S corp. They need preferred shares for investors, which would immediately disqualify the election.
The grocery store still must observe every corporate formality that a C corporation does: annual meetings, separate financial records, board documentation. The S election changes how profits are taxed, not how the entity is governed.
How Each Structure Is Taxed
The tax differences across structures are large enough to shift thousands of dollars a year, so it is worth comparing them directly.
- Sole proprietorships and general partnerships: All net business income passes through to the owner’s individual tax return and is subject to federal income tax at rates ranging from 10 to 37 percent for 2026. The self-employed owner also pays a 15.3 percent self-employment tax on net earnings, which covers both the employee and employer shares of Social Security and Medicare.5Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes)
- LLCs: Taxed the same as sole proprietorships (single-member) or partnerships (multi-member) by default, including self-employment tax on active members’ shares of income. An LLC can elect corporate taxation if that produces a better result.1Internal Revenue Service. Limited Liability Company (LLC)
- S corporations: Profits pass through to shareholders and are taxed at individual rates. Only the owner’s salary, not distributions, is subject to payroll taxes. The IRS requires that salary to be reasonable for the work performed, so you cannot pay yourself a token wage and take the rest as distributions.
- C corporations: Profits are taxed at a flat 21 percent corporate rate, and dividends paid to shareholders are taxed again at the shareholder’s individual rate.2Office of the Law Revision Counsel. 26 USC 11 – Tax Imposed
One significant change for 2026: the 20 percent qualified business income deduction that pass-through owners have used since 2018 expired at the end of 2025.6Internal Revenue Service. Qualified Business Income Deduction Unless Congress extends or replaces it, pass-through income in 2026 is taxed at the full individual rate, which makes the relative tax cost of each structure worth recalculating with a tax professional.
When Liability Protection Disappears
Forming an LLC or corporation does not guarantee that your personal assets are permanently safe. Courts can pierce the veil, setting aside the entity’s separate legal status and holding the owners personally liable, when the business is being used as a personal alter ego rather than a legitimate independent operation. The behaviors that trigger it look mundane until a lawsuit arrives.
The most common factors courts look at:
- Commingling funds. Paying your rent from the business account, depositing business revenue into your personal account, or using the company credit card for personal expenses. Once the line between business money and personal money blurs, a court can conclude there was never a real separation to begin with.
- Undercapitalization. Forming a company with almost no capital and loading it with obligations it obviously cannot meet. This suggests the entity exists to absorb liability rather than to operate a real business.
- Ignoring corporate formalities. Failing to hold required meetings, keep minutes, file annual reports, or maintain an operating agreement. If you don’t treat the entity as separate from yourself, courts won’t either.
- Using business assets for personal purposes. Funding vacations, buying personal furniture, or paying personal bills through the company, all of which erode the entity’s independence in a court’s eyes.
Fraud is not required. Courts pierce veils in cases where the owners simply didn’t bother maintaining the separation. A grocery store family that runs personal expenses through the store’s account, never holds an annual meeting, and keeps no board minutes has quietly dismantled the very protection they formed the corporation to create.
How to Form a Business Entity
The formation process starts with a few decisions and a state filing. You will need a business name that is distinguishable from any entity already registered in the state, a registered agent with a physical address in the state who can accept legal documents during business hours, and the address of the company’s principal office.
The core formation document is called articles of organization for LLCs or articles of incorporation for corporations, though some states use names like certificate of organization or certificate of formation. These documents typically require the entity’s name, the registered agent’s name and address, and the purpose or duration of the business. You file them with the Secretary of State, usually through an online portal, and pay a filing fee that varies by state and entity type.
After the state approves the filing and issues a certificate confirming the entity’s existence, the next step is applying for an Employer Identification Number from the IRS. Partnerships and corporations need one, and most single-member LLCs will need one too if they plan to open a business bank account or hire employees. The application is free and can be completed online in minutes.7Internal Revenue Service. Get an Employer Identification Number The IRS recommends forming your entity with the state before applying, since the EIN application may be delayed otherwise.
Keeping the Structure Alive After Formation
Filing the formation documents is the beginning, not the end. Nearly every state requires LLCs and corporations to file periodic reports, usually annually and sometimes biennially, updating the state on the company’s current address, registered agent, and officers or managers. Failing to file typically results in late fees, and if the company falls far enough behind, the state can administratively dissolve the entity or revoke its good standing. Losing good standing can strip away the liability protection that was the whole point of forming the entity.
Businesses that operate in multiple states face an additional layer. If your LLC is formed in Delaware but conducts substantial business in Texas, Texas will require you to register there as a foreign entity and obtain a certificate of authority. There is no single revenue or transaction threshold that triggers this requirement. It depends on the nature and extent of your activity in each state. The most serious consequence of skipping foreign qualification is being barred from filing lawsuits in that state’s courts, so you cannot enforce your own contracts there until you register and pay any back fees or penalties.
On the federal side, domestically formed companies are currently exempt from beneficial ownership reporting requirements with FinCEN.8FinCEN.gov. Beneficial Ownership Information Reporting Foreign-formed entities registered to do business in the U.S. still must file. That exemption resulted from a 2025 rule change, so it is worth monitoring in case Congress or FinCEN revisits the requirement.