Most small business owners pick an entity type once — usually whatever their attorney or a quick Google search suggested — and never revisit it. That’s a mistake that can cost tens of thousands of dollars over the life of a business. The structure sitting on your state filing isn’t just a legal formality; it’s the single biggest lever you control on your annual tax bill. This guide walks you through exactly how each common entity type is taxed, where the real savings opportunities live, and what you need to do to capture them.
Understand the Default Tax Treatment Before You Change Anything
Every entity type has a default position with the IRS. If you’ve never made an election or received a notice confirming otherwise, you’re almost certainly being taxed under that default — and it may not be optimal for your income level.
Sole Proprietorship and Single-Member LLC
If you’re a one-person operation and you formed an LLC without making any tax election, the IRS treats you as a disregarded entity. Your business income flows directly onto Schedule C of your personal Form 1040. You pay ordinary income tax on the net profit — and, critically, you pay self-employment (SE) tax of 15.3% on the first $168,600 of net earnings (2024 threshold) and 2.9% on everything above that. There is no separation between “business income” and “your salary.” Every dollar of profit is subject to SE tax.
For a business clearing $60,000 in net profit, that SE tax alone is roughly $8,478 before a single dollar of income tax is calculated. Most people who form a single-member LLC thinking it saves them money on taxes are surprised to learn it saves them nothing compared to a sole proprietorship — the liability protection is real, but the tax treatment is identical.
Multi-Member LLC
Add a second member and the IRS default shifts to partnership taxation. The LLC files Form 1065, issues K-1s to each member, and each member reports their share of income on their personal return. SE tax treatment for partners is nuanced — general partners pay SE tax on their distributive share; limited partners generally don’t, though the IRS has been scrutinizing this aggressively. If your multi-member LLC has two equal partners each taking $80,000 in distributions, both are typically paying SE tax on their full share.
C Corporation
A C corp is a fully separate taxpayer. It pays a flat 21% federal corporate income tax on its profits. When it distributes dividends to shareholders, those shareholders pay tax again — either 15% or 20% qualified dividend rates depending on income level. This double taxation is the famous downside of C corp status for small businesses. However, for businesses that reinvest most profits rather than distributing them, or those planning a venture-capital raise (VCs almost universally require C corp structure), the math can favor it.
The S Corp Election: Where Most Small Business Owners Find Real Savings
The S corp election is the most commonly used tax strategy for profitable small businesses, and it’s frequently misunderstood. An S corp is not a separate entity type you form at the state level — it’s a federal tax election you make on an existing corporation or LLC by filing IRS Form 2553.
Here’s the core mechanic: an S corp is a pass-through entity like an LLC, so profits still flow to your personal return and avoid double taxation. But unlike a standard LLC, an S corp splits your income into two buckets: a reasonable salary (which is subject to payroll taxes — the equivalent of SE tax) and distributions (which are not subject to payroll taxes). That split is where the savings come from.
A Concrete Example of S Corp Tax Savings
Say your business nets $150,000 in profit. As a single-member LLC (disregarded entity), you’d owe SE tax on the full $150,000 — approximately $17,730 after the deductible half of SE tax is factored in.
With an S corp election and a reasonable salary of $70,000 (which must reflect market rates for your role — the IRS watches this closely), you’d pay payroll taxes only on that $70,000. The remaining $80,000 passes through as a distribution with no SE/payroll tax. Payroll taxes on $70,000 come to roughly $10,710. That’s a savings of approximately $7,000 per year — for the cost of filing Form 2553 and running a simple payroll.
At $200,000 in net profit with a $90,000 salary, annual savings often exceed $10,000. The crossover point where an S corp election typically starts making sense is generally around $40,000–$50,000 in annual net profit, once you account for the additional compliance costs (payroll processing, an extra tax return via Form 1120-S).
How to Make the S Corp Election
- Confirm eligibility. S corps can have no more than 100 shareholders, only one class of stock, and all shareholders must be U.S. citizens or resident aliens. Partnerships and most corporations cannot be S corp shareholders.
- File Form 2553. Submit to the IRS no later than two months and 15 days after the beginning of the tax year you want the election to apply to. For calendar-year businesses, that’s March 15. Miss the deadline and you’re waiting until next year — or filing for late election relief, which the IRS does grant in many cases.
- Set up payroll. You must pay yourself a reasonable salary and run actual payroll — withholding federal and state income tax, Social Security, and Medicare. Services like Gusto or QuickBooks Payroll handle this for roughly $50–$100/month for a single employee.
- File Form 1120-S annually. This is the S corp informational return, due March 15. It generates a K-1 that flows to your personal 1040.
Partnership and Multi-Member LLC: When It Actually Makes Sense
Partnership taxation isn’t inherently worse than S corp treatment — it’s just different, and it offers flexibility that S corps don’t. Partners can have different economic arrangements (different profit splits, preferred returns, special allocations) that aren’t possible in an S corp’s single-class-of-stock structure. Real estate partnerships, for instance, regularly use special allocations to pass depreciation to investors who need it most.
A multi-member LLC with two active partners can also elect S corp status, which can reduce SE tax for both members — but the restrictions become more complex when multiple owners are involved. Each partner’s reasonable salary needs to be defensible, and any future equity arrangements need to stay within S corp rules.
C Corp: Not Just for Startups Anymore
The 2017 Tax Cuts and Jobs Act dropped the corporate rate to a flat 21%, which changed the calculus for some small businesses. If you’re in the 37% individual bracket and your business reliably retains most of its earnings for reinvestment, you might actually pay less tax leaving money inside a C corp at 21% than passing it through to your personal return at 37%.
The trap: when you eventually take that money out — as salary, dividends, or liquidation proceeds — you face a second layer of tax. The C corp strategy only works if you have a genuine long-term plan for how the money exits, whether that’s a sale of the business (where qualified small business stock exclusions under IRC Section 1202 can eliminate capital gains tax entirely on up to $10 million in gains), or structured distributions over time.
For most service-based small businesses under $500,000 in revenue that distribute most of their profits annually, C corp status is almost always the wrong call.
State Taxes Add Another Layer — Don’t Ignore Them
Federal entity tax treatment is only half the picture. Several states impose additional taxes on pass-through entities or LLCs specifically. California charges LLCs an annual franchise tax of $800 minimum plus an additional fee based on gross receipts — an LLC earning $1 million in California pays $6,000 in franchise taxes before a dollar of federal or state income tax is calculated. New York City imposes its own unincorporated business tax on partnerships and sole proprietors. Tennessee taxes investment income earned by LLCs.
Some states have introduced pass-through entity (PTE) taxes as a workaround to the $10,000 SALT deduction cap — allowing the entity to pay state income tax at the entity level (fully deductible federally) rather than at the individual level (capped). As of 2024, over 30 states have enacted PTE tax regimes. If you’re in a high-tax state and haven’t asked your accountant about this, you’re likely leaving money on the table. The Tax Foundation maintains a current tracker of which states have enacted these rules.
How to Decide Which Structure Is Right for You Right Now
Entity type decisions aren’t permanent. You can convert, elect, or restructure — though some changes have tax consequences. Here’s a practical decision framework:
- Under $40,000 net profit: Single-member LLC or sole proprietorship. Keep it simple. S corp compliance costs eat the savings.
- $40,000–$500,000 net profit, single owner or simple ownership: S corp election on your existing LLC is usually the highest-value move. Run the numbers with your CPA using your actual salary and profit figures.
- Multiple owners with complex equity arrangements: Multi-member LLC taxed as a partnership, potentially with S corp election if ownership is simple enough.
- Planning to raise venture capital or use Section 1202 QSBS exclusion: C corp, ideally Delaware.
- High-tax state: Layer in PTE tax analysis regardless of entity type.
Common Mistakes to Avoid
The most expensive mistake is making the S corp election without setting up real payroll — the IRS can recharacterize distributions as wages, triggering back payroll taxes plus penalties. A close second is setting an unreasonably low salary to maximize distribution income; “reasonable compensation” is fact-specific, and the IRS has successfully challenged salaries of $0 and $10,000 for owners billing out at $200/hour. Third: converting a C corp to an S corp without understanding the built-in gains tax — if the C corp has appreciated assets, switching to S corp doesn’t immediately escape corporate-level tax on those gains for a 5-year recognition period. Finally, don’t assume last year’s optimal structure is still optimal this year. If your revenue crossed a significant threshold, revisit the analysis annually.
