S-Corp vs. LLC vs. C-Corp: How I'd Actually Advise a Client Choosing a Business Structure

Educational guide — a CPA's real-world walkthrough of entity selection, updated for 2026 tax law

Every year, business owners ask some version of the same question: "Should I be an LLC, an S-corp, or a C-corp?" There's no universal right answer — it depends on income level, growth plans, and what you're optimizing for. Here's how I'd actually walk a client through it, with the specific mechanics that matter under current (2026) tax law.

Start With the Baseline: What Each One Actually Is

• LLC (Limited Liability Company) — a state-law legal entity, not a federal tax classification. By default, a single-member LLC is taxed as a disregarded entity (like a sole proprietorship) and a multi-member LLC is taxed as a partnership. An LLC can also elect to be taxed as an S-corp or C-corp.
• S-corp — a federal tax election (Form 2553), not a separate legal entity type. An LLC or a corporation can elect S-corp taxation if it qualifies (generally under 100 shareholders, one class of stock, U.S. individuals/certain trusts as owners).
• C-corp — the default tax treatment for a corporation that hasn't elected S-corp status. It's a separate taxpaying entity in its own right, taxed at a flat 21% federal rate.

The legal liability protection (keeping your personal assets separate from business debts) is essentially the same across an LLC, S-corp, and C-corp — the differences that matter most are almost entirely about taxation, not liability.

The Self-Employment Tax Angle: Why People Elect S-Corp Status

If you're a sole proprietor or a single-member LLC (taxed as a disregarded entity), all of your net business profit is subject to self-employment tax — 15.3% on top of regular income tax, covering both the "employee" and "employer" shares of Social Security and Medicare.

Electing S-corp status changes this. As an S-corp owner who also works in the business, you become a W-2 employee of your own company. You pay yourself a "reasonable salary" — subject to normal payroll tax (the same 15.3%, split as 7.65% employee / 7.65% employer, with the corporation paying its half) — and any additional profit is distributed to you as a shareholder distribution, which is not subject to self-employment or payroll tax at all.

This is the core tax play behind S-corp elections: the salary portion pays payroll tax; the distribution portion doesn't. For a profitable small business, that split can mean real savings.

The catch, and it's a big one: the IRS requires your salary to be "reasonable" for the work you actually do — comparable to what an unrelated employee would be paid for the same role. Paying yourself an artificially low salary and taking most of your profit as distributions to dodge payroll tax is a well-known audit target, and the IRS has successfully recharacterized distributions as wages (with back payroll taxes and penalties) in numerous court cases. The savings are real, but only within the bounds of a defensible salary.

Practical takeaway: S-corp elections generally start making sense once net business profit is comfortably above what a reasonable salary for the owner's role would be — commonly cited around $60,000–$80,000+ of net profit, though the right number depends on the specific role and industry. Below that, the payroll administration cost and complexity of running an S-corp often isn't worth it yet.

LLC Advantages: Flexibility First

An LLC's biggest strength is flexibility, not any one specific tax break:

• Liability protection with far less formality than a corporation — no required board meetings, minutes, or corporate formalities in most states.
• Pass-through taxation by default — profits and losses flow to your personal return, avoiding entity-level tax.
• Choice of tax treatment — an LLC can stay a disregarded entity/partnership, or elect S-corp or even C-corp taxation later, without changing its legal structure.
• The Qualified Business Income (QBI) deduction under Section 199A applies to LLC (and S-corp) profit passed through to owners — a permanent 20% deduction on qualified business income as of the One Big Beautiful Bill Act (OBBBA), with 2026 phase-out thresholds starting at $201,750 (single) / $403,500 (married filing jointly), and a new $400 minimum deduction for anyone with at least $1,000 of qualifying business income. This deduction is not available to C-corp income.

For a lot of small, single-owner businesses — especially in the early stages — a simple LLC (no S-corp election) is the right starting point precisely because of this flexibility. You can always elect S-corp taxation later once profit justifies it.

Home Office and Mileage: Where the Rules Genuinely Differ by Entity

This is one of the most misunderstood areas, and the entity type actually changes the mechanics significantly.

Sole proprietors and single-member LLCs (disregarded entities): You deduct home office expenses directly on Schedule C (via Form 8829) and business mileage directly against business income. Straightforward — no extra structure needed.

S-corp owners: This is where it gets more complicated. Since 2018, the tax code has suspended the miscellaneous itemized deduction for unreimbursed employee business expenses — and the OBBBA has now made that suspension permanent. That matters because an S-corp owner is technically an employee of their own corporation, and home office or mileage expenses paid personally are, technically, unreimbursed employee expenses. Without a fix, those costs are simply non-deductible to anyone — the owner can't deduct them personally, and the S-corp can't deduct them because the S-corp didn't pay them.

The fix is a written Accountable Plan. Under IRS rules (IRC §62(c)), the S-corp formally reimburses the owner for substantiated business expenses — home office percentage, business mileage at the IRS standard rate, and similar costs. Done correctly:

• The S-corp deducts the reimbursement as a business expense
• The owner receives the reimbursement completely tax-free (it isn't wages, and isn't subject to payroll tax)

Without an accountable plan in place, S-corp owners are quietly losing legitimate deductions every year. If you've elected S-corp status and don't have a written accountable plan and a regular reimbursement routine, that's a gap worth closing.

Asset Protection: What Actually Changes, and What Doesn't

LLCs, S-corps, and C-corps all generally provide a liability shield — creditors of the business generally can't reach the owner's personal assets (home, personal bank accounts, personal investments) solely because the business owes money or gets sued, as long as the entity is respected as separate from its owner.

That "as long as" matters. Courts can disregard the entity ("pierce the corporate veil") if you:

• Commingle personal and business funds
• Fail to maintain basic formalities (separate bank accounts, contracts in the entity's name, etc.)
• Undercapitalize the entity to the point it can't plausibly meet its obligations
• Use the entity to commit fraud

Practically speaking, an LLC and a corporation offer similar liability protection — the corporation just comes with more required formality (minutes, bylaws, more rigid record-keeping) to maintain that protection, while an LLC's operating agreement can be simpler. Neither structure protects you from your own personal negligence (e.g., a contractor personally causing an injury is still personally liable for that act, regardless of entity), and neither protects against a personally-guaranteed business loan.

C-Corp: The Flat Rate, and What It's Really For

A C-corp pays a flat 21% federal tax rate on its profits — regardless of how much it earns. Compare that to individual rates, which climb up to 37% at higher income levels for pass-through owners.

Where this matters most: retained earnings. If a profitable business doesn't need to distribute all its profit to the owner — because it's reinvesting in growth, building a cash reserve, or simply doesn't need the owner to pull the money out yet — a C-corp lets that profit sit and grow inside the company taxed at a flat 21%, rather than flowing through to the owner's personal return and being taxed immediately at potentially much higher individual rates (as would happen automatically with an LLC, partnership, or S-corp, whether or not the owner actually takes the cash out).

The trade-off is double taxation. When a C-corp does distribute profit to its owner as a dividend, that dividend is taxed again on the owner's personal return — meaning the same dollar of profit can be taxed once at the corporate level and again at the individual level. This is the classic knock against C-corps, and it's very real if you plan to regularly pull most profit out as cash compensation to yourself.

A less-known C-corp advantage for the right business: Qualified Small Business Stock (Section 1202). If a C-corp qualifies (domestic C-corp, gross assets under $75 million at issuance under current law, engaged in an active qualifying trade or business — notably excluding most service businesses like consulting, accounting, law, and similar fields), an owner who holds the stock long enough can potentially exclude up to $15 million of capital gain (or 10 times their basis, whichever is greater) from federal tax when they eventually sell their shares. Under recent law changes, you no longer need the full five-year holding period to get some benefit — three years gets a 50% exclusion, four years gets 75%, and five-plus years gets the full exclusion. For a business planning a future sale or exit — particularly a scalable, non-service business — this is a significant reason founders sometimes choose C-corp status from the start, or convert into one, even before profitability makes the flat 21% rate itself compelling.

How I'd Actually Advise a Client

• Just starting out, modest profit, testing the business: A simple LLC (or even sole proprietorship) is usually right. Keep it simple; you can elect S-corp status later once profit justifies the added payroll complexity.
• Established, profitable service business, one or a few owners actively working in it: An LLC electing S-corp taxation is the common sweet spot — self-employment tax savings on the distribution portion, QBI deduction eligibility, and manageable complexity, as long as a written accountable plan is in place for home office/mileage and a defensible reasonable salary is set.
• Planning to raise outside investment, scale significantly, or eventually sell the company for a large gain — especially in a non-service industry: A C-corp is worth serious consideration, both for investor familiarity (VCs generally prefer C-corps) and for potential QSBS gain exclusion on an eventual sale.
• Profitable business that doesn't need to distribute most of its cash to the owner right now: The C-corp's flat 21% rate on retained earnings can be genuinely attractive — but only if you're disciplined about not needing to pull that cash out as compensation soon, since that's when double taxation bites.

None of these are permanent decisions carved in stone — businesses convert between structures as circumstances change. But the right starting point depends heavily on current profit level, how much cash the owner needs to personally take out versus reinvest, and long-term exit plans.

This article is for general educational purposes only and does not constitute tax, legal, or financial advice. Entity selection has significant, fact-specific tax and legal consequences, and mistakes (such as an indefensible S-corp salary or a poorly documented accountable plan) can be costly if challenged. Consult a qualified CPA and, for liability and formation questions, a business attorney, before choosing or changing your business structure.

Tax Code References

• IRC §1361–§1379 — S corporation eligibility, election, and operating rules; election made via Form 2553.
• IRC §1401 — Self-employment tax (15.3% combined Social Security/Medicare on net self-employment earnings).
• Reasonable compensation case law — David E. Watson, P.C. v. United States, 668 F.3d 1008 (8th Cir. 2012); Joly v. Commissioner, T.C. Memo. 1998-361 — both involving IRS recharacterization of S-corp distributions as wages where salary was found unreasonably low.
• IRC §199A — Qualified Business Income (QBI) deduction; sunset provision repealed and made permanent by the One Big Beautiful Bill Act (OBBBA), Pub. L. 119-21 (signed July 4, 2025); 2026 phase-in/phase-out thresholds set per IRS Revenue Procedure 2025-32.
• IRC §67(g) — Suspension of miscellaneous itemized deductions (including unreimbursed employee business expenses), originally enacted by the Tax Cuts and Jobs Act (TCJA) of 2017 through 2025, made permanent by OBBBA.
• IRC §62(c) and Treas. Reg. §1.62-2 — Accountable plan rules governing tax-free reimbursement of employee business expenses, including by S-corp owner-employees.
• IRC §162 — General rule for deducting ordinary and necessary trade or business expenses.
• IRC §11 — Flat 21% corporate income tax rate, enacted by the TCJA and unchanged by OBBBA.
• IRC §1202 — Qualified Small Business Stock (QSBS) gain exclusion; gross asset threshold, exclusion cap, and holding-period rules amended by OBBBA for stock issued after July 4, 2025 (new gross asset limit of $75 million; exclusion cap increased to the greater of $15 million or 10× basis; tiered 50%/75%/100% exclusion for 3/4/5-plus year holding periods).
• IRS Revenue Procedure 2025-32 — 2026 annual inflation adjustments for individual tax brackets, standard deduction, QBI thresholds, and related figures cited throughout.

Tax law changes frequently, including through annual inflation adjustments and new legislation. Figures and thresholds above reflect the law as of this writing (2026) and should be verified against current IRS guidance before relying on them.