C-Corp vs. S-Corp: Tax Rates, Double Taxation, QSBS, and Which Structure Wins
The C-Corp and S-Corp are both corporations under state law, but they are taxed completely differently. A C-Corp is a separate taxpayer: it pays a flat 21% federal corporate income tax on its profits (Form 1120), and when those profits are distributed to shareholders as dividends, the shareholders pay tax again at qualified dividend rates (0%, 15%, or 20% plus the 3.8% NIIT). This “double taxation” is the C-Corp’s primary disadvantage. An S-Corp is a pass-through entity: the corporation itself pays no federal income tax (Form 1120-S), and all income passes through to shareholders on Schedule K-1, taxed at their individual rates (10-37%). The S-Corp avoids double taxation entirely. However, the C-Corp has advantages in specific situations: the 21% corporate rate is lower than most individual rates for retained earnings, the QSBS exclusion (IRC 1202) can eliminate capital gains tax on a sale, and C-Corps can deduct the full cost of employee fringe benefits (including for owner-employees above 2% shareholders).
C-Corp vs. S-Corp tax comparison:
| Factor | C-Corp | S-Corp |
|---|---|---|
| Entity-level tax | 21% flat rate | None (pass-through) |
| Shareholder tax on distributions | Qualified dividend rates (0/15/20%) | No additional tax (already taxed on K-1) |
| Total tax on distributed profits | 21% + 15-20% = approximately 36-40% | Individual rates (10-37%) + SE tax on salary |
| Retained earnings tax rate | 21% (no shareholder tax until distributed) | Individual rates (10-37%, taxed even if not distributed) |
| QBI deduction (Section 199A) | NOT eligible | Eligible (20% deduction for qualifying income) |
| FICA on owner compensation | 15.3% on wages (same as S-Corp) | 15.3% on salary only (distributions exempt) |
| Fringe benefits for owner-employee | Fully deductible (health insurance, group term life, etc.) | Not deductible for 2%+ shareholders (included in W-2) |
| QSBS exclusion (IRC 1202) | Eligible (up to $10M tax-free gain on sale) | NOT eligible |
| Accumulated earnings penalty | 20% surtax on unreasonable accumulations | No penalty (pass-through) |
| Number of shareholders | Unlimited | Maximum 100 |
| Shareholder types | Any (individuals, corps, trusts, foreigners) | Restricted (US individuals, certain trusts, no corps) |
| Classes of stock | Multiple (common, preferred, etc.) | One class only |
When the C-Corp wins:
| Scenario | Why C-Corp Is Better |
|---|---|
| Planning to sell for $1M+ and holding 5+ years | QSBS: $0 federal tax on up to $10M gain |
| Retaining earnings for growth (not distributing) | 21% corporate rate < 32-37% individual rate |
| Significant fringe benefits for owner | Health insurance, group term life fully deductible |
| Venture capital / investor funding | Multiple stock classes, unlimited shareholders |
| Foreign shareholders | S-Corp cannot have non-resident alien shareholders |
When the S-Corp wins:
| Scenario | Why S-Corp Is Better |
|---|---|
| Distributing most profits to owners annually | Avoids double taxation |
| FICA savings needed (salary/distribution split) | Distributions not subject to FICA |
| QBI deduction available (non-SSTB under threshold) | 20% deduction reduces effective rate |
| Simple ownership (1-2 US shareholders) | Pass-through simplicity |
| Lifestyle business (not planning to sell) | No double tax, no entity-level tax |
How do the numbers compare at different income levels?
What is double taxation and how does it affect C-Corp owners?
A C-Corporation pays federal income tax at a flat 21% rate on its taxable income, and when the corporation distributes after-tax profits as dividends to shareholders, those dividends are taxed again at the shareholder level. Qualified dividends are taxed at preferential rates (0%, 15%, or 20%), but the combined effective rate still exceeds the rate on pass-through income in most cases. Strategies to mitigate double taxation include paying reasonable salaries and bonuses to owner-employees (deductible by the corporation), maintaining an accountable plan for expense reimbursements, and retaining earnings for legitimate business growth rather than distributing them. The accumulated earnings tax (IRC 531) imposes a 20% penalty on earnings retained beyond the reasonable needs of the business, so indefinite retention is not a free strategy.
What entity structure works best for a business with multiple owners?
A multi-member LLC taxed as a partnership is the most flexible default. It files Form 1065 and issues K-1s to each member, with the operating agreement controlling profit allocation, voting rights, and buyout terms. An S-Corp works if all owners are US individuals (no entity or foreign owners), the business has no more than 100 shareholders, and everyone agrees on equal-class stock. A C-Corp is necessary if you want venture capital (preferred stock classes), have foreign owners, or plan to retain significant earnings at the 21% corporate rate. LLCs offer the most flexibility for unequal profit splits, special allocations, and varying capital contributions.
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Yarik Yarosh, CPA. "C-Corp vs. S-Corp: Tax Rates, Double Taxation, QSBS, and Which Structure Wins." Blue Cloud CPA, September 5, 2026. https://bluecloudcpa.com/guides/small-business-c-corp-vs-scorp-tax-comparison
This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.