This guide is general legal information, not legal advice, and does not create an attorney–client relationship. Rules change and vary by state — verify current requirements with official sources or a licensed attorney.
Three questions decide most entity choices: Who is liable if the business is sued or fails? How will profits be taxed? And who must approve decisions? Answer those, and the choice among an LLC, a corporation, and a partnership usually answers itself. This guide compares the main U.S. business structures on exactly those axes, then explains the piece founders most often miss — that state-law entity type and federal tax classification are two separate choices, and the IRS lets many entities pick their tax treatment.
Entities are formed under state law (each state has its own LLC and corporation statutes), while the IRS and state revenue agencies decide how they are taxed. Keep those layers distinct and the comparison becomes much clearer.
Key takeaways
- Sole proprietorships and general partnerships require no filing but leave owners personally liable; LLCs and corporations shield personal assets if properly maintained.
- By IRS default, a single-member LLC is disregarded for income tax and a multi-member LLC is taxed as a partnership; eligible entities can elect corporate treatment on Form 8832.
- An S corporation is a tax status, not an entity type: pass-through taxation for domestic entities with 100 or fewer qualifying shareholders and one class of stock, elected on Form 2553.
- C corporations pay entity-level tax (with possible double taxation of dividends) but remain the standard vehicle for venture capital and public markets.
- Liability protection depends on conduct after formation — separation of finances, adequate records, and signing in the entity's name — not just the certificate.
The lineup: five structures in brief
The Small Business Administration's guide frames the standard menu:
- Sole proprietorship. The default for one person doing business without registering an entity. Simple, but the owner is personally liable for all business debts and obligations.
- Partnership. The default when two or more people carry on a business for profit. General partners manage and are personally liable; limited partnerships (LPs) and limited liability partnerships (LLPs) modify that exposure for some or all partners. A written partnership agreement is essential even though the entity can exist without one.
- Limited liability company (LLC). A state-law entity combining limited liability for all owners ("members") with flexible management and pass-through taxation by default. Formed by filing articles of organization; governed internally by an operating agreement.
- C corporation. A separate legal person owned by shareholders, managed by a board of directors and officers. Strongest fit for raising capital through stock, but the most formal and the only structure taxed at the entity level by default.
- S corporation. Not a distinct entity under state law but a federal tax election available to qualifying corporations (and LLCs that choose corporate classification), passing income through to owners' returns.
| Structure | Personal liability | Default federal tax | Formation filing | Typical fit |
|---|---|---|---|---|
| Sole proprietorship | Unlimited | Owner's individual return (Schedule C); self-employment tax | None (licenses aside) | Solo, low-risk, testing an idea |
| General partnership | Unlimited, joint and several | Pass-through (Form 1065, K-1s) | None required; agreement recommended | Small co-owned ventures, transitional stage |
| LLC | Limited for all members | Disregarded (1 member) or partnership (2+); may elect corporate status | Articles of organization + state fee | Most small and mid-sized private businesses |
| C corporation | Limited for shareholders | Entity-level corporate tax; dividends taxed again to shareholders | Articles of incorporation + bylaws | Venture-backed startups, businesses reinvesting profits or going public |
| S corporation | Limited (underlying entity) | Pass-through with shareholder eligibility limits | Underlying entity filing + Form 2553 | Profitable owner-operated companies seeking payroll-tax planning |
The liability question: shields and their limits
The core promise of LLCs and corporations is that business creditors reach business assets, not the owner's house or savings. The shield has real limits. Owners remain liable for their own wrongful acts, for debts they personally guarantee (which lenders routinely require from small businesses), and for certain obligations like withheld payroll taxes. Courts can also "pierce the veil" — disregard the entity — where owners commingle funds, ignore formalities, or use the entity to perpetrate fraud.
That makes post-formation discipline part of the structure decision: separate bank accounts, contracts signed in the entity's name, documented major decisions, and adequate capitalization. Corporations carry the heaviest formalities (boards, annual meetings, minutes); LLCs are lighter but not zero. Our guide to corporate governance for private companies covers what maintenance actually looks like.
The tax layer: defaults and elections
Federal tax classification is where entity choice gets interesting, because it is partly elective.
Default rules
Under the IRS's entity-classification ("check-the-box") regulations, described on the IRS's LLC page, a domestic LLC with one member is disregarded — its income lands directly on the owner's return — while an LLC with two or more members is taxed as a partnership. Either way there is no entity-level income tax by default, though the LLC remains separate for employment and certain excise taxes. Corporations formed under state incorporation statutes are taxed as C corporations unless they elect otherwise.
Electing differently
An eligible entity can override its default with Form 8832, choosing treatment as a corporation, a partnership, or a disregarded entity. The election can be effective up to 75 days before filing or 12 months after, and once made generally cannot be changed again for five years. Separately, a qualifying domestic corporation — or an LLC treated as one — can elect S corporation status on Form 2553. The IRS's S corporation requirements: no more than 100 shareholders, who must generally be individuals (plus certain trusts and estates), no partnership, corporate, or nonresident-alien shareholders, and only one class of stock.
Practical note: "LLC taxed as an S corp" is a common small-business structure because S status can reduce self-employment taxes on profits above a reasonable owner salary — but it adds payroll obligations and eligibility constraints, and the math depends on profit levels and state taxes. Run the numbers with a tax professional before electing; elections are easy to make and awkward to unwind.
Capital, investors, and growth plans
Growth plans often decide the question regardless of tax preferences. Institutional venture investors overwhelmingly expect a C corporation — frequently a Delaware one — because preferred stock classes, option pools, and familiar governance documents do not map cleanly onto LLC membership interests, and S corporation shareholder limits exclude funds entirely. A bootstrapped services firm faces none of those pressures and usually values pass-through taxation more. Raising from the public rather than from funds adds its own structural demands, because an online Regulation Crowdfunding raise must run through a registered funding portal, caps what the company can take in over twelve months, and leaves it with a crowd of small holders to keep on the cap table. Structure also shapes exits: acquirers scrutinize entity history and records in M&A due diligence, and a clean single-entity story is an asset. If the road ever turns rough, entity type likewise frames the options in a business bankruptcy or reorganization.
State-law choices: where and how to form
Formation is a state filing, and states differ on fees, annual franchise taxes, publication requirements, and statutory flexibility. Delaware's corporate law and courts make it the default for companies seeking outside investment, but a small business operating in one state usually does best forming at home: forming elsewhere still requires registering (and paying) as a foreign entity where you actually operate. Whatever the state, the internal agreement — operating agreement, bylaws, or partnership agreement — is where owners allocate control, profits, transfer rights, and deadlock solutions, and it deserves more attention than the filing itself. The same discipline applies to the company's external paperwork; see our overview of the contract clauses that control risk.
A basic formation checklist
- Confirm name availability and register the entity with the state; appoint a registered agent.
- Adopt the internal governing document (operating agreement, bylaws, or partnership agreement) — signed by all owners.
- Obtain an EIN from the IRS; open a dedicated business bank account.
- Make any tax elections (Form 8832 or Form 2553) within their deadlines.
- Check state and local licenses, permits, and registrations, plus foreign qualification in other operating states.
- Document initial capital contributions and issue ownership interests or shares properly.
- Calendar annual report and franchise-tax deadlines to keep the entity in good standing.
Owners, workers, and ongoing costs
Two recurring operational points round out the decision. First, classification of the people who do the work is a separate legal question from entity type: hiring help through an LLC does not settle whether workers are employees or contractors, an issue with its own tests covered in our guide to worker classification. Second, budget for carrying costs, which vary widely by state — annual report fees, franchise taxes (California, for example, imposes a minimum annual franchise tax on LLCs and corporations), registered-agent fees, and tax-return preparation for partnerships and corporations. A structure that saves modest tax but adds compliance friction may not pay for itself at small scale.
Frequently asked questions
Is an LLC always better than a sole proprietorship?
Not always, but the case is strong once real liability exposure or revenue exists. The SBA characterizes sole proprietorships as fit for low-risk ventures and idea-testing; an LLC adds a liability shield and credibility for modest filing and annual costs. Insurance matters under either structure — a shield against contract creditors does not replace coverage for accidents or professional errors.
What is the real difference between an S corp and a C corp?
Tax treatment and ownership limits. Both are corporations under state law with the same liability shield. A C corporation pays corporate income tax, and shareholders pay tax again on dividends; an S corporation passes income through to shareholders' returns but must stay within the 100-shareholder, one-class-of-stock, no-entity-and-no-nonresident-alien-shareholder limits. Growth companies raising institutional money generally need C status.
Can I change my structure later?
Yes — businesses routinely convert (many states offer statutory conversion, for example LLC to corporation) or change only their tax classification via Form 8832 or Form 2553. But changes can trigger tax consequences, and the IRS generally locks in a classification election for five years. Starting simple and upgrading is a legitimate strategy; just get tax advice before each step.
Do I need to form my company in Delaware?
Only if your plans call for it — typically outside investors or complex stock structures. A local business gains little from Delaware and still must register and pay fees as a foreign entity in its home state, doubling compliance. Form where you operate unless investors, multistate operations, or specific legal features point elsewhere.
Making the call
Work the three questions in order. If personal liability exposure is meaningful, that rules out proprietorships and general partnerships. If profits will be distributed to owner-operators, pass-through treatment (LLC default or S election) usually wins the tax comparison; if profits will be reinvested or investors are coming, the C corporation earns its complexity. Then let governance preferences and state costs break ties. Put the decision in writing with a real operating agreement or bylaws, calendar the compliance dates, and revisit the structure at each inflection point — first hire, first investor, first seven-figure year. More guides live in our business and corporate law hub. This article is general information, not legal or tax advice; entity choice depends on your state's statutes and your tax picture, so confirm the details with a business attorney and a CPA.
