C Corporation vs. S Corporation: Which Tax Structure Is Right for Your Business?

An S corporation is a C corporation that filed one form. Both are ordinary corporations under state law, formed with the same charter and governed by the same statute. The difference is a federal tax election made on IRS Form 2553, and it changes who pays tax on the profits, not how the company is organized.

That distinction matters because founders often treat this as a fork in the road at formation. It is closer to a setting than a structure, in the sense that a machine built one way can be run on different settings. The entity stays the same. The tax treatment changes, and so does the list of people allowed to own it.

We’ll cover:

• What a C corporation is

• What an S corporation is

• The key differences

• The advantages of each

• How to choose

• What it costs to switch later

What is a C corporation?

A C corporation is the default. Incorporate in any state, do nothing further, and subchapter C of the Internal Revenue Code applies: the company pays federal tax on its profits at 21%, and shareholders pay again when profits are distributed as dividends. That second “layer” is what people mean by double taxation.

The trade for that second layer is flexibility. A C corporation can have an unlimited number of shareholders, issue multiple classes of stock, and count funds, foreign investors and other companies among its owners. Every US-listed company you can name is a C corporation, because no S corporation may exceed 100 shareholders.

One further point rarely makes the comparison articles, and it is the reason most venture-backed startups never consider an S election. Qualified small business stock (QSBS) under IRC § 1202 must be stock in a C corporation. S corporation stock does not qualify, and for stock acquired after July 4, 2025, the capital gains tax exclusion runs up to $15 million per issuer, per stockholder, so the difference is not academic.

What is an S corporation?

An S corporation is a corporation that has elected to be taxed under subchapter S, so its income is passed through to shareholders and reported on their personal returns. The company itself generally pays no federal income tax.

The election is made on Form 2553, and the deadline bites: to take effect for a given tax year, it must generally be filed within two months and fifteen days of the start of that year. Late elections can sometimes be fixed through IRS relief procedures, which is more work than filing on time.

Eligibility is the constraint that decides most cases:

• Domestic corporation only. Certain financial institutions, insurance companies and domestic international sales corporations are excluded.

• No more than 100 shareholders. Members of a family may be counted as a single shareholder under IRC § 1361(c)(1), which helps more than the headline number suggests.

• Individuals, estates and certain trusts only. Partnerships, corporations and most trusts cannot hold S corporation stock. This is what rules out venture funds, not the shareholder cap.

• No nonresident alien shareholders. A US-resident founder qualifies; a co-founder living abroad generally does not.

• One class of stock. Differences in voting rights are permitted, so voting and non-voting common is fine. A preferred stock round is not.

An LLC can also elect C corporation or S corporation treatment, which is how many small businesses reach this point without ever forming a corporation.

What are the key differences between a C corporation and an S corporation?

Taxation

A C corporation pays 21% federally on profits, and shareholders pay again on dividends. An S corporation passes profits and losses through to shareholders, who pay at their individual rates whether or not cash is distributed—this is similar to a partnership. Losses passing through can be useful early, subject to the basis, at-risk and passive activity limits.

Neither is automatically “cheaper.” A business that makes profit and distributes most of its profit each year usually does better under an S election. A business consuming growth capital infusion, retaining earnings to fund growth, or heading for an exit where § 1202 is in play, usually does better as a C corporation.

Ownership

C corporations take any shareholder and any number of share classes. S corporations take up to 100 eligible shareholders and one class of stock. If you expect to grant preferred stock, take money from a fund, or add a co-founder outside the US, the S election closes off before you get there.

Accounting method

This one is commonly stated wrongly. C corporations are not required to use accrual accounting across the board. Under IRC § 448(c), a C corporation may use the cash method if its average annual gross receipts for the prior three years do not exceed an inflation-adjusted threshold, which is $32 million for tax years beginning in 2026 under Rev. Proc. 2025-32. Below that line, the choice of method is open to C and S corporations alike.

Payroll and self-employment tax

A shareholder who works in an S corporation must take reasonable compensation as W-2 salary, and only the remaining distributions escape employment tax. “Reasonable” has no bright line and is a recurring audit issue, so the saving is real but not unlimited, and it comes with the cost of running payroll and filing a separate return.

Corporate formalities

There is no difference. Annual meetings, minutes, stock records and state filings are functions of state corporate law, which does not know or care how you are taxed. Any source telling you an S corporation carries a lighter governance burden is describing something that does not exist.

State and local treatment

States do not all follow the federal election. California taxes S corporation net income at 1.5% and imposes an $800 minimum franchise tax, per the Franchise Tax Board. New York City does not recognize S status for its General Corporation Tax, so a company operating in the city can face entity-level tax anyway. Model the state cost before you rely on the federal saving.

What are the advantages of a C corporation and an S corporation?

Advantages of a C corporation

• Investor-ready ownership: unlimited shareholders, multiple classes of stock, and no restriction on funds or foreign holders. This is the structure the venture financing documents assume.

• Section 1202 eligibility: stock may qualify as QSBS, with a tiered exclusion of 50%, 75% or 100% of gain at three, four and five years for stock acquired after July 4, 2025.

• Retained earnings at 21%: profits reinvested in the business are taxed once, at the corporate rate, until they are distributed. A growing company that pays no dividends never reaches the second layer.

• Equity compensation that works: option pools, restricted stock and multiple classes are straightforward, and employees and advisors expect them.

Advantages of an S corporation

• One layer of tax: profits are taxed to the shareholders only, which suits a company that distributes most of what it earns.

• Employment tax saving on distributions: amounts above a reasonable salary are not subject to employment tax, which is the main reason profitable owner-operated businesses make the election.

• Losses pass through: early losses can offset a shareholder’s other income, subject to basis and the at-risk and passive activity rules.

• No entity-level federal tax to plan around: distributions of already-taxed income are generally tax-free to the extent of basis, which simplifies cash planning for a small ownership group.

How do I choose between a C corporation and an S corporation?

Three questions usually settle it:

1. Are you raising institutional money in the next two years? If yes, choose a C corporation and stop there. A fund cannot hold S corporation stock, and preferred stock breaks the one-class rule, so the election would have to be revoked before the round closes anyway.

2. Will the business distribute its profits or retain them? A services business distributing cash to a few US individuals is the classic S corporation. A company reinvesting everything it earns gets less from the election and gives up § 1202 to have it.

3. Where do you and your shareholders pay tax? Run the state numbers. California’s 1.5% and New York City’s General Corporation Tax can absorb much of the federal saving, and a co-founder living overseas ends the analysis on its own.

What does it cost to switch later?

Switching is possible in both directions, and neither is free.

Electing S status for an existing C corporation can trigger the built-in gains tax under IRC § 1374 on appreciation that existed at conversion, if those assets are sold within the five-year recognition period. Revoking an S election is simpler, but once it is terminated or revoked, the company generally cannot elect again for five tax years without IRS consent under IRC § 1362(g).

Converting from an S corporation to a C corporation also starts the § 1202 clock from the date of conversion rather than from when you started the business. If a venture round is likely and § 1202 matters to you, the timing of that conversion is worth planning rather than discovering.

The takeaway

Pick the tax treatment that matches how the money will move, and revisit it when that changes. The election is reversible; the cost of reversing it at the wrong moment is not.

We work on corporate structuring for growth companies and coordinate with your accountant on the tax modeling. Get in touch if you are deciding now.

This article is general information, not tax or legal advice for any specific situation. Confirm the numbers with your tax adviser before you rely on them.