S Corp vs. C Corp vs. LLC: Tax and Personal Liability Implications for Owners

The entity you choose shapes three things that matter for the rest of your business's life: how much tax you pay, how exposed your personal assets are to business problems, and how easily you can move money between yourself and the business. Pick well and the structure fades into the background. Pick poorly and you fight your entity choice every April for years.

This guide walks through the three most common structures — LLC, S corporation, and C corporation — in the order most owners should think about them. Not alphabetically. Not in the order the IRS publishes them. In the order that matches how real businesses evolve.

The first thing to understand is that "LLC" and "S corp" are not in the same category. An LLC is a legal entity created under state law — a container for liability protection. An S corp is a federal tax election — a rule about how the IRS taxes a container. You can have an LLC that's taxed as an S corp. You can have a corporation that's taxed as an S corp. You cannot have an LLC that's taxed as an LLC, because "LLC" isn't a tax classification. By default, a single-member LLC is taxed as a sole proprietorship, and a multi-member LLC is taxed as a partnership.

That distinction matters because the real decision is a two-dimensional one: what legal entity you form at the state level, and what tax classification you elect at the federal level. Most owners conflate the two and get confused about why their tax outcome doesn't match what their lawyer told them.

Here's the shorter answer first. In terms of personal liability protection, an LLC and a corporation (either S or C) give you substantially similar protection. Both create a legal separation between you and the business. Both mean that if the business gets sued, the plaintiff generally can't reach your house, car, or personal bank accounts to satisfy a judgment.

The protections have limits. If you personally guarantee a business debt, the guarantee is what exposes you personally — the entity type doesn't matter. If you commit a tort yourself (you personally rear-end someone in a company vehicle), you're personally liable regardless of entity. If you sign contracts in your own name rather than as an officer of the entity, you may have personally contracted. If you commingle funds or fail to observe corporate formalities, a court may pierce the veil (covered in 1.5).

The short version: entity choice matters far more for taxes than for liability. Don't pick an S corp over an LLC because you think it protects you better. It doesn't.

This is where entity choice actually moves your finances. Here's what happens by default at each entity:

Single-member LLC (default): Taxed as a sole proprietorship. All net business income flows to Schedule C on your personal 1040. You pay ordinary income tax on all of it, plus self-employment tax (15.3% on the first ~$168,600 and 2.9% Medicare above that, with an additional 0.9% at higher incomes) on all of it.

Multi-member LLC (default): Taxed as a partnership. Files Form 1065, issues K-1s to members. Active members pay self-employment tax on their share of the income.

Corporation without S election (default): C corporation. The entity itself pays corporate income tax on its profits (currently 21% federal). When profits are distributed to shareholders as dividends, those dividends are taxed again on the shareholder's personal return. This is the "double taxation" of C corps.

Corporation or LLC with S election: S corporation. The entity itself pays no federal income tax. Profits flow through to shareholders proportionally. Shareholder-employees must be paid reasonable W-2 compensation, on which payroll tax applies. Remaining profits flow through as distributions, which are not subject to self-employment tax.

The S corp election is the headline tax-saving move for most profitable small businesses. A sole proprietor making $200,000 pays self-employment tax on essentially all of it. An S corp shareholder-employee making the same $200,000 can pay themselves, say, $80,000 as W-2 salary (payroll tax on $80,000) and take $120,000 as a distribution (no payroll tax). The self-employment tax savings on the $120,000 is roughly 15% of it, or $18,000 per year. Real money.

But — and this is critical — the IRS requires "reasonable compensation" for shareholder-employees. You can't pay yourself $10,000 and take $190,000 as distributions. The "reasonable" figure depends on your industry, your role, and what comparable W-2 employees would earn. The tax benefit of the S corp election scales with the spread between your salary and your total income, and aggressive spreads get scrutinized.

Most small business guides dismiss the C corp as "the double-taxed one." That oversimplifies a real planning tool. C corps win in several specific situations:

Retained earnings for growth. If you're reinvesting nearly all profits back into the business rather than pulling them out, the C corp's 21% rate can be lower than your personal marginal rate on pass-through income. You only face double taxation when you distribute — so if you're not distributing, you're effectively at 21%.

Venture-scale fundraising. Institutional investors generally require C corp structure. If you're raising priced equity rounds, you'll convert to a C corp eventually. Starting as one can save you the conversion headache.

Qualified Small Business Stock (QSBS). Section 1202 lets founders exclude up to $10 million of gain on sale of C corp stock held for 5+ years, if the business qualifies. This is one of the most valuable tax benefits in the code, and it's C corp only.

Fringe benefits. C corps can offer owner-employees benefits (like certain health reimbursement arrangements, group term life, and some education benefits) on a tax-favored basis that S corps can't match for 2%+ shareholders.

Section 303 redemption. Covered in detail in 1.4 and 7.3. For C corp owners with taxable estates, this provision is a major reason to stay in a C corp structure.

Section 199A gives pass-through owners (sole props, partnerships, S corps) a potential deduction of up to 20% of qualified business income. The deduction has phase-outs, limitations for specified service trades, and a complicated interaction with W-2 wages and qualified property. At full strength, it meaningfully narrows the gap between pass-through taxation and the C corp's 21% rate.

This deduction is one reason the S corp election remains attractive for many profitable service businesses even at higher income levels. It's also one of the most likely provisions to change legislatively, so planning around it requires ongoing attention.

For most owners, the decision sequence looks like this:

If net business income is under ~$40,000: Stay an LLC taxed as sole proprietorship or partnership. The S corp payroll administration cost (typically $1,500–$3,000/year) eats the tax savings.

If net business income is $40,000–$150,000+: Make the S corp election. Set up payroll, pay yourself a reasonable salary, take the rest as distributions. The self-employment tax savings compound meaningfully.

If you're reinvesting nearly all profits or raising priced equity: Consider C corp. Talk to a CPA about QSBS eligibility.

If you have partners with materially different involvement: Partnership taxation (LLC taxed as partnership) gives you flexibility in allocating income and losses that an S corp (with its single-class-of-stock rule) doesn't.

If you're forming something you might sell within 5 years: The difference between an asset sale and a stock sale, and the tax treatment of each, matters more than the default entity taxation. Talk to an M&A-focused tax advisor before you commit.

Entity choice isn't free. The real cost stack includes:

• Formation cost: $100–$1,500 depending on state, entity type, and whether you use a lawyer.
• Annual state fees: Some states (California, Massachusetts, Delaware) charge meaningful franchise taxes or annual report fees.
• Tax prep cost: A partnership or S corp return typically runs $1,000–$3,500. A C corp return similar. A sole proprietorship adds maybe $300–$600 to a personal return.
• Payroll cost: S corp shareholder-employees need payroll. That's a payroll provider ($600–$1,500/year) plus bookkeeping time.
• Switching cost: Converting from one entity or tax classification to another can trigger tax events and state-level complications.

Add these up. The right entity for your $60,000/year side business is not the right entity for a $600,000/year operation, and the right entity for that isn't the right entity for a $6 million operation that's about to raise Series A.

Most owners pick an entity once and never revisit. The right rhythm is to review entity structure every time one of these triggers fires:

• Net income crosses $50,000 and again at $150,000.
• You add or lose a partner.
• You start hiring W-2 employees.
• You raise outside capital.
• You start planning for exit.
• You get married, divorced, or have a significant change in spouse's income.
• A material change in tax law happens (and watch for the 199A deduction's sunset).

The entity that was right at startup is rarely the entity that's right at scale. Revisiting isn't a failure of the original decision — it's good management of a high-leverage choice.