S Corp vs C Corp: The Real Differences for a Small Business

October 29, 2026

Every corporation starts out as a C corp for federal tax purposes. An S corp is a corporation, or an LLC, that has filed an election to be taxed differently. The legal company can be identical. What changes is who pays the tax on the profit and how many times it gets taxed.

Here’s how the two compare for a small business, with a simple example of what double taxation actually costs.

The core difference: one layer of tax or two

A C corp is a separate taxpayer. It files Form 1120 and pays federal income tax on its own profit at a flat 21%. When it pays dividends to its owners, those owners pay tax again on their personal returns. That’s the double taxation people talk about.

An S corp generally doesn’t pay federal income tax itself. It files Form 1120-S, and the profit passes through to the owners on Schedule K-1. Each owner pays tax on their share at their own rates, whether or not the money is distributed. The profit is taxed once.

What double taxation looks like

Say a C corp earns $100,000 of profit and pays out everything left after tax as a dividend.

That’s an effective rate of about 33% on profit the owner takes home. With an S corp, the same $100,000 passes through and is taxed once at the owner’s rate, and many owners also qualify for the 20% qualified business income deduction, which the 2025 federal tax law made permanent.

This example is simplified. It leaves out salary, state tax and the 3.8% net investment income tax that applies at higher incomes. It still shows why most small, owner-run businesses that take their profit out each year lean toward S corp status.

Side by side

When a C corp can make sense

Double taxation only bites when profit leaves the company. A C corp can be the better fit when:

• You plan to reinvest most of the profit in the business instead of paying it out. The 21% rate can be lower than your personal rate.
• You’re raising money from investors, especially venture funds, who usually can’t or won’t hold S corp stock.
• You want more than one class of stock, such as preferred shares for investors.
• You may sell the company down the road and could qualify for the qualified small business stock exclusion under Section 1202. For stock issued after July 4, 2025, the exclusion can cover up to $15 million of gain, with partial exclusions after three or four years and a full exclusion after five, if the company and the stock meet the rules.

When an S corp usually makes sense

• You run an owner-operated business and take most of the profit out each year
• You want profit taxed once, on your own return
• You and any co-owners are eligible shareholders
• You can pay yourself a reasonable salary through payroll and want the payroll tax savings on the rest

For most service businesses, contractors and professional practices we work with in Oklahoma, the S corp is the more common choice. Startups planning to raise outside money are the main exception.

What about Oklahoma taxes?

The state picture follows the same pattern. Oklahoma taxes C corps at a flat 4% corporate income tax rate, and dividends paid to owners are taxed again on their personal Oklahoma returns. An S corp files Oklahoma Form 512-S, and the profit flows to the owners’ individual returns, where Oklahoma’s top individual rate for 2026 is 4.5%. Owners who live in other states may have tax withheld or need to file there too, so multi-state ownership is worth planning for.

Fringe benefits work differently

This is a difference owners often miss. A C corp can usually provide health insurance and other fringe benefits to owner-employees and deduct the cost, with the benefit staying tax-free to the owner. In an S corp, an owner with more than 2% of the stock is treated more like a partner for many benefits. Health insurance premiums the S corp pays for that owner get added to their W-2 wages, though the owner can often deduct them on the personal return. For a business with large benefit costs, this can narrow the gap between the two.

Reasons owners pick the wrong one

• Choosing a C corp because “corporations look more professional,” without planning to reinvest profit
• Choosing an S corp before the business makes enough profit to cover the cost of payroll and an extra return
• Forming in a different state to save fees, then owing taxes and filings in both states anyway
• Planning to raise investor money as an S corp and having to restructure later

Can you switch later?

Yes, in either direction, but with limits. A C corp can elect S corp status by filing Form 2553, though a former C corp may face a built-in gains tax if it sells assets it owned before the switch. An S corp can revoke its election and become a C corp, but it generally can’t elect S status again for five years. Because of those limits, the decision is worth getting right the first time.

FAQ

Is an S corp or a C corp better for a small business?

For most owner-run small businesses that pay out their profit, an S corp results in less total tax because profit is taxed once. A C corp can be better for businesses that reinvest heavily or plan to raise investor money.

Do S corps pay any tax at the company level?

Usually not federal income tax, though a former C corp can owe built-in gains tax or tax on excess passive income in some cases. State rules vary.

Is a C corp the same as an LLC?

No. A C corp is a corporation taxed as a separate entity. An LLC is a different legal structure that can be taxed as a sole proprietorship, a partnership, an S corp or a C corp.

Can an LLC be taxed as a C corp?

Yes. An LLC can elect corporate tax treatment by filing Form 8832, and it can then elect S corp status with Form 2553 if it qualifies.

Talk it through before you file

Epsilon Accounting Solutions helps owners in Edmond, Oklahoma City and across Oklahoma choose the right entity and tax status, then handles the formation, the election and the returns. Call (405) 458-8949 or book a time on our contact page.

Book a Consultation