C Corporation vs. S Corporation

Same Entity, Different Tax Election

A C corporation and an S corporation aren't two different kinds of business entity. Every corporation is formed the same way, by filing articles of incorporation with a state, and every corporation is taxed as a C corporation by default. S corporation status is a federal tax election a corporation can make, by filing IRS Form 2553, if it meets the eligibility rules. Once the election is in place, the IRS taxes the business as an S corporation going forward, but it's still the same legal corporation under state law, with the same bylaws, board, and stock.

How a C Corporation Is Taxed

A C corporation pays federal income tax on its own profit using Form 1120. When the corporation later distributes profit to shareholders as a dividend, shareholders pay tax on that dividend again on their personal returns, and the corporation gets no deduction for the dividend it paid. This two-layer structure is commonly called double taxation. A C corporation can reduce or defer this by retaining earnings in the business rather than distributing them, though retaining profit for no real business purpose can trigger the separate accumulated earnings tax.

How an S Corporation Is Taxed

An S corporation files an informational return, Form 1120-S, but generally doesn't pay federal income tax itself. Instead, its income, deductions, and credits pass through to shareholders in proportion to their ownership, reported to each on a Schedule K-1, and taxed once on the shareholders' personal returns. This avoids the double taxation a C corporation faces on distributed profit, which is the main reason closely held, profitable corporations elect S status.

Ownership Rules Are Where the Two Diverge Most

A C corporation can have an unlimited number of shareholders of any type, including other corporations, partnerships, foreign individuals and entities, and multiple classes of stock with different rights. An S corporation is far more restricted: per the IRS, it can have no more than 100 shareholders, who must be individuals, certain trusts, or estates, not partnerships, corporations, or nonresident aliens, and it can issue only one class of stock, though differences in voting rights alone don't violate that rule. A corporation that wants outside investment from a venture fund, a corporate investor, or a foreign national generally can't do that while an S corporation election is in place.

Why Startups Raising Capital Stay C Corporations

Venture capital funds are structured in ways that generally can't hold S corporation stock, and most standard venture financing terms assume a C corporation. C corporation stock can also qualify for the Section 1202 qualified small business stock exclusion, under 26 U.S.C. Section 1202, which lets an individual shareholder exclude some or all of the gain on qualifying stock held more than five years; this exclusion is available only to C corporation stock, not to an S corporation or other pass-through interest. These two factors are why a startup planning to raise institutional capital almost always stays, or becomes, a C corporation rather than electing S status.

Self-Employment and Payroll Tax Treatment

An S corporation shareholder who works in the business must be paid a reasonable salary through payroll, subject to payroll tax, before taking further profit as a distribution; that additional distribution generally isn't subject to self-employment tax, which is the tax savings many owners are after when electing S status. A C corporation shareholder who works in the business is simply an employee paid a salary like any other employee; the corporation's separate profit is taxed to the corporation, not passed through to the shareholder as self-employment income at all.

State Tax Treatment Can Differ

Most states follow the federal S corporation election for state income tax purposes, but a handful of states tax S corporations differently, require a separate state-level election, or impose an entity-level tax regardless of the federal election. Check your specific state's treatment before assuming your state tax bill follows the federal pattern exactly. For the full process and deadline to make the election, see how to elect S corporation tax status.

The Election Is a Tax Decision, Not a One-Time Setup Step

A corporation can elect S status after it's already operating as a C corporation, and it can later revoke that election, though revoking it generally bars re-electing S status again for five years without IRS consent. Treat the choice as a multi-year commitment rather than something to toggle based on a single good or bad year.

Check Every Shareholder Against the Eligibility Rules First

If any current or prospective shareholder is a corporation, a partnership, another LLC, or a nonresident alien, the business can't make or keep an S corporation election, no matter how profitable it is or how much the owners would otherwise save. Confirm every shareholder's eligibility before planning around the election.

Reasonable Compensation Is Enforced, Not Optional

The IRS and courts have repeatedly required S corporation shareholder-employees to take a reasonable salary for work performed before taking additional profit as a distribution; setting salary unreasonably low specifically to avoid payroll tax is a well-documented audit target, not a gray area to plan around aggressively.

A Corporation Can Only Have One Federal Tax Status at a Time

A corporation is either taxed as a C corporation or, if it has a valid S election on file, as an S corporation; it can't be partly one and partly the other for federal purposes. If ownership changes in a way that breaks eligibility, for example a corporate or nonresident alien shareholder buys in, the S election generally terminates automatically, and the corporation reverts to C corporation tax treatment for the rest of that tax year.

This Is Not Tax Advice

Whether a C corporation or an S corporation fits your business depends on your profit level, ownership plans, and whether you expect to raise outside capital. Talk to a tax professional before electing or revoking S corporation status.