S Corporation Restrictions: Ownership, Stock, and Tax Rules

S corporation restrictions cover four main areas: who can own the stock, how the stock is structured, how owner-employees are paid, and how profits are distributed. Break almost any of them and the S election terminates, often retroactively to the date of the violation, which puts the company back into C corporation double taxation and locks it out of re-electing for five years. The rules come from the tax code’s requirements to qualify under Subchapter S, and they apply on the effective date of the election and every day after.

Which Corporations Can Elect S Status

Only a domestic corporation, or a domestic entity eligible to be treated as one, can file Form 2553 and make the election. The filing must be made no later than two months and 15 days after the beginning of the tax year the election should take effect, or at any time during the preceding tax year.¹ Miss that window and the company is a C corp for the year unless it qualifies for late-election relief.

Some corporations can never elect. Insurance companies taxed under Subchapter L, financial institutions using the reserve method for bad debts, and current or former domestic international sales corporations (DISCs) are permanently disqualified.²

Who Can Own the Shares

The eligible shareholder list is short: U.S. citizens and resident aliens, estates, certain qualifying trusts, and tax-exempt organizations described in sections 401(a) and 501(c)(3) of the tax code.² That means qualified retirement plans and charities can hold S corp stock, a category many owners overlook.

Everyone else is barred. Partnerships, LLCs taxed as partnerships, C corporations, other S corporations, and nonresident aliens cannot own shares.³ This is where accidental terminations happen most often. A shareholder who moves abroad and loses U.S. resident status, or an estate that distributes shares to an ineligible beneficiary, can destroy the election for the whole company on the day it happens.

The 100-Shareholder Cap

An S corporation is limited to 100 shareholders.³ The count is more forgiving than it looks. A married couple and their estates count as one shareholder. All members of a family count as one shareholder as long as they descend from a common ancestor no more than six generations removed from the youngest generation of shareholders, and the definition sweeps in spouses, former spouses, and legally adopted or foster children.² Family businesses can add relatives without bumping into the cap in most cases.

Trusts as Shareholders

Not every trust qualifies. Only four types can hold S corp stock: grantor trusts, voting trusts, qualified subchapter S trusts (QSSTs), and electing small business trusts (ESBTs). When the grantor of a grantor trust dies, the trust remains eligible for two years, after which it must convert to a QSST or ESBT or dispose of the shares. Putting stock into any other kind of trust, or leaving it in an unconverted grantor trust past the two-year window, terminates the election.

The One Class of Stock Rule

An S corp can have only a single class of stock, meaning all outstanding shares must carry identical rights to distributions and liquidation proceeds.² Voting rights are the one permitted difference: voting and non-voting common stock are fine. But any agreement that gives one group a larger cut of profits or a priority claim in liquidation creates a second class, and the election terminates immediately.

Shareholder loans can trip this rule. If the IRS reclassifies a loan as equity and that equity provides economic rights different from the common stock, it counts as a second class. The tax code provides a “straight debt” safe harbor for loans that qualify. The debt must be a written, unconditional promise to pay a fixed dollar amount on demand or by a specific date. The interest rate and payment dates cannot depend on corporate profits or the borrower’s discretion, the debt cannot be convertible into stock, and the creditor must be an eligible S corp shareholder or an active lending business.⁴ Debt that meets every element is safe even if it would otherwise look like equity.

Reasonable Compensation for Shareholder-Employees

Every shareholder who performs more than minor services for the corporation must receive a W-2 salary reflecting fair market value before taking any distributions.⁵ Salaries are subject to Social Security and Medicare tax; distributions are not. Paying a token salary and pulling the rest as distributions is the fastest way to trigger an S corp audit.

Courts have held that a shareholder’s stated intent to limit their own salary is irrelevant. What matters is whether the compensation reasonably reflects the services actually performed.⁶ The IRS looks at training and experience, duties and time commitment, what comparable businesses pay for similar roles, dividend history, and what non-shareholder employees earn. If rank-and-file staff earn more than an owner doing similar work, expect scrutiny. When the IRS reclassifies distributions as wages, the corporation owes back employment taxes plus interest and penalties.

Pro Rata Distributions

Every distribution must go out in exact proportion to each shareholder’s ownership percentage. A 40% owner gets 40% of every distribution, every time.⁷ The same rule governs allocations of income, losses, deductions, and credits. Special allocations and the flexible profit-splitting that partnerships and multi-member LLCs allow are not available.

Disproportionate distributions violate the single-class-of-stock rule, and the S election terminates as of the date of the violation. In a 2024 Tax Court case, an S corp founder was held liable for taxes on income he never actually received because the corporation had overdistributed to other shareholders. Track every dollar leaving the corporation and keep the math proportional to ownership.

Fringe Benefits for More-Than-2% Owners

Any shareholder who owns more than 2% of the stock, counting direct and constructive ownership, is treated like a partner in a partnership for fringe benefit purposes.⁸ Benefits that ordinary employees receive tax-free, including employer-paid health insurance, group-term life over $50,000, and dependent care assistance, become taxable income for these owners.

Health insurance is where owners most often get the paperwork wrong. Premiums the corporation pays for a more-than-2% shareholder must appear in W-2 Box 1 wages for income tax, but not in Boxes 3 or 5, because they are not subject to Social Security or Medicare tax. The shareholder then claims the self-employed health insurance deduction on the personal return. Mishandling the W-2 either creates unnecessary payroll tax or costs the shareholder the deduction.

Two Taxes Only Former C Corps Face

Corporations that converted from C to S status and still carry accumulated earnings and profits from the C years face two entity-level taxes. Companies that have always been S corps do not.

Excess Passive Investment Income

If more than 25% of gross receipts come from passive sources such as interest, dividends, rents, royalties, or annuities, and the company has accumulated C corp earnings and profits, the corporation owes a corporate-level tax on the excess passive income at the highest corporate rate (currently 21%).⁹ Three consecutive years over the 25% threshold, and the S election terminates automatically on the first day of the next year.¹⁰ Distributing out the accumulated C corp earnings and profits ends the exposure entirely.

Built-In Gains

Assets that appreciated while the company was a C corp carry a built-in gain into the S years. Selling those assets within five years of the election means the corporation owes tax on the net recognized built-in gain at the highest corporate rate, 21%.¹¹ The PATH Act of 2015 made the five-year recognition period permanent. After year five, the extra tax goes away.

Loss Deductions on the Shareholder’s Return

An S corp shareholder who wants to deduct a loss on their personal return has to clear four separate limitations, applied in order.¹²

Basis. Losses are capped at the shareholder’s combined stock basis and debt basis. Stock basis starts with the purchase price and moves with income, contributions, and distributions; debt basis comes from loans the shareholder personally makes to the corporation. Excess losses are suspended and carry forward, but they expire permanently if the shareholder sells the stock while basis is at zero.
At-risk. Even with basis, losses are deductible only to the extent the shareholder is personally on the hook. Money and property contributed count, as do amounts borrowed under personal liability. Nonrecourse loans secured only by the S corp stock do not.
Passive activity. A shareholder who does not materially participate in the business can only use the losses against other passive income. Suspended passive losses free up when the shareholder disposes of the entire interest to an unrelated party.
Excess business loss. For tax years before 2029, aggregate business losses over $305,000 for single filers or $610,000 for joint filers (adjusted for inflation) are disallowed and roll forward as a net operating loss.

Form 7203 records the basis calculation and must be attached to the individual return any year a shareholder claims a loss, receives a distribution, disposes of stock, or gets a loan repayment.¹³

Tax Year Requirement

An S corp must use a calendar year ending December 31 unless it has a legitimate business reason for a different fiscal year.¹⁴ The two escape hatches are a Section 444 election (which requires a deposit that offsets the deferral benefit) or IRS approval based on a genuine business purpose.¹⁵ Most S corps stick with December 31.

State Treatment Varies

The S election is federal. States are not obligated to follow it. Most honor it and tax S corp income only at the shareholder level, but some impose their own entity-level taxes, ranging from minimum franchise taxes to flat income taxes on S corp earnings, and a few do not recognize the election at all. An S corp operating in more than one state has to check each state’s rules separately rather than assume federal pass-through treatment carries over.

What Happens if the Election Terminates

Violating any restriction ends the S election, usually retroactively to the date of the violation. The corporation reverts to C status and pays tax at the corporate level, and shareholders pay again on distributions.

Once terminated, the corporation cannot re-elect S status for five tax years beginning after the first year the termination took effect.¹⁶ The IRS can waive the wait, but only if the corporation shows the terminating event was not reasonably within its control and not part of a plan to end the election. A change in majority ownership (more than 50% of stock held by shareholders who were not owners at the time of termination) helps the case for a waiver.

For genuinely inadvertent problems, such as governing documents that accidentally create disproportionate distribution rights, the corporation can seek relief under Section 1362(f). It must show the termination was inadvertent, that the corporation and shareholders acted in good faith, and that everyone filed returns consistent with S corp status. The traditional route is a private letter ruling, which historically costs $38,000 or more in user fees. The IRS has also published streamlined procedures that let corporations self-correct common errors, including defective operating agreements, without a private letter ruling, provided the IRS has not already discovered the issue and no disproportionate distributions were actually made.

A late-filed Form 2553 has its own path. Revenue Procedure 2013-30 grants automatic relief when the only failure was missing the deadline, all shareholders reported income as if the election were in place, and the IRS has not flagged the issue within six months of the first S corp return being filed.¹⁷ There is no outside time limit on that relief as long as those conditions still hold.

1
Internal Revenue Service. Instructions for Form 2553
2
Office of the Law Revision Counsel. 26 U.S. Code 1361 – S Corporation Defined
3
Internal Revenue Service. S Corporations
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Office of the Law Revision Counsel. 26 USC 1361 – S Corporation Defined
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Internal Revenue Service. S Corporation Employees, Shareholders and Corporate Officers
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Internal Revenue Service. Wage Compensation for S Corporation Officers
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eCFR. 26 CFR 1.1377-1 – Pro Rata Share
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Office of the Law Revision Counsel. 26 U.S. Code 1372 – Partnership Rules to Apply for Fringe Benefit Purposes
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eCFR. 26 CFR 1.1375-1 – Tax Imposed When Passive Investment Income of Corporation Having Subchapter C Earnings and Profits Exceeds 25 Percent of Gross Receipts
10
Office of the Law Revision Counsel. 26 U.S. Code 1362 – Election; Revocation; Termination
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Office of the Law Revision Counsel. 26 U.S. Code 1374 – Tax Imposed on Certain Built-In Gains
12
Internal Revenue Service. S Corporation Stock and Debt Basis
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Internal Revenue Service. About Form 7203, S Corporation Shareholder Stock and Debt Basis Limitations
14
eCFR. 26 CFR 1.1378-1 – Taxable Year of S Corporation
15
Internal Revenue Service. About Form 8716, Election to Have a Tax Year Other Than a Required Tax Year
16
Office of the Law Revision Counsel. 26 USC 1362 – Election; Revocation; Termination
17
Internal Revenue Service. Revenue Procedure 2013-30