C Corporation Uses and Traps

How it works

A corporation is a C corporation by default; nothing has to be elected for that to be true. What separates it from every pass-through structure is that it is a taxpayer in its own right, paying its own tax under Section 11(b) at a flat 21 percent rate, with no graduated brackets and no special add-on rate for a personal-service corporation. The Tax Cuts and Jobs Act, Public Law 115-97, set that rate as permanent for tax years beginning after 2017, and the 2025 tax act, Public Law 119-21, left it untouched.

The catch is what happens when the money leaves. A dividend to a shareholder is taxed again, generally at the 20 percent qualified dividend rate plus the 3.8 percent net investment income tax, on top of the 21 percent already paid at the entity level. Combined, the federal rate on a fully distributed dollar reaches approximately 39.8 percent, worse than paying the top individual rate of 37 percent a single time. A pass-through owner is taxed only once, whether the profit is kept in the business or taken out. That tension resolves in the corporation's favor in three situations.

• The earnings stay inside the corporation. Undistributed profit has paid only the 21 percent entity-level tax and keeps compounding rather than moving to the shareholder through a second layer of tax.
• Deductible fringe benefits a pass-through cannot match. Health insurance is the clearest example: a C corporation can generally deduct it for an owner-employee without adding the value back to wages, while a shareholder owning more than two percent of an S corporation must add the premium back to W-2 income.
• Qualified small business stock (QSBS). Section 1202 allows a large, sometimes total, exclusion of gain on selling stock in a qualifying C corporation, available for C corporation stock only. For a founder building toward a stock sale, this is usually the actual reason a C corporation gets chosen.

What this is worth in Florida

Less than the federal analysis suggests. Florida has no individual income tax, so a Florida S corporation owner already pays nothing at the state level on income the business passes through. A Florida C corporation gets no equivalent break: Florida imposes its own 5.5 percent corporate income tax on top of the 21 percent federal rate, a cost the pass-through never faces, which tilts the default toward a pass-through for a Florida business that plans to distribute what it earns.

Who this applies to

Every domestic corporation starts as a C corporation. Nothing has to be filed for that to be true; a corporation stops being one only if it affirmatively elects S status. Because there is no income threshold or size test to simply be a C corporation, the real question for most businesses is not whether they can be one. It is whether they should stay one.

• Reinvesting operating and product companies fit well. A business plowing its profit back into growth, inventory, people, or equipment pays only the entity-level tax on what it earns, because nothing has been distributed yet. If the plan includes an eventual sale of the stock itself rather than a sale of the business's assets, this is also the fact pattern where Section 1202 becomes available.
• A service business that distributes everything it earns generally does not fit. Without reinvestment and without Section 1202 in play, nothing offsets the double tax. A Florida service business in that position is usually better served by a pass-through structure, a question I map out in my Florida S-corp guide.
• A professional service business cannot use Section 1202 at all. The statute's definition of a qualified trade or business excludes health, law, accounting, consulting, financial services, and brokerage as professional services, along with banking or financing, farming, extraction, and hospitality. A CPA practice, a law firm, or a consulting shop does not qualify no matter how it is structured, which is why the QSBS benefit belongs mainly to operating and product businesses rather than to most professional practices.

Deciding among a C corporation, an S corporation, and a partnership for a specific business is a bigger question than any one provision answers, and it is the subject of my entity choice decision tree.

What it requires

Staying a C corporation costs nothing beyond doing nothing. Getting real value from one, through deferral, fringe benefits, or Section 1202, has specific conditions attached.

The basic mechanics

A C corporation gets its own employer identification number and files its own annual return, Form 1120, due the fifteenth day of the fourth month after year-end, with a six-month extension available. It is a separate filer from its shareholders in every sense, the same fact that creates the double-tax exposure in the first place.

What Section 1202 demands

Every condition below has to hold for the stock to qualify at all.

• Domestic C corporation status at issuance and for substantially all of the holding period; a conversion at the wrong time can break this.
• A $75,000,000 ceiling on the corporation's aggregate gross assets, tested before and immediately after issuance, indexed for inflation beginning in 2027. The ceiling for stock issued before the 2025 change was $50,000,000.
• Original issuance. The stock must come directly from the corporation for money, property other than stock, or services; a secondary purchase from another shareholder does not qualify.
• A qualified trade or business, with at least 80 percent of the corporation's assets used in its active conduct.

For stock acquired after July 4, 2025, the exclusion percentage ramps with the holding period:

Stock acquired on or before that date keeps the older schedule, and for most holders that is better than it sounds rather than worse. Stock acquired after September 27, 2010 carries a 100 percent exclusion under Section 1202(a)(4); the February 17, 2009 to September 27, 2010 window carries 75 percent; the 50 percent base rate in Section 1202(a)(1)(A) reaches back to stock acquired before February 18, 2009. None of it is available before the five-year mark.

The exclusion is also capped per issuer, at the greater of $15,000,000 for stock acquired after July 4, 2025 (indexed from 2027; $10,000,000 for older stock), or ten times the shareholder's adjusted basis in the stock disposed of that year. When the corporation was capitalized with appreciated property rather than cash, that basis is floored at the property's fair market value on the contribution date, not its lower cost, so a property contribution can support a far larger cap than the dollar figure suggests.

Reasonable compensation runs the other way from an S corporation

An S corporation's problem is paying an owner too little, so profit passes through as a lower-taxed distribution instead of wages. A C corporation's version runs the other way: because wages are deductible and dividends are not, the incentive is to pay too much, and the exposure is the IRS recharacterizing the excess as a disguised, nondeductible dividend. A defensible salary, set to what an unrelated employer would pay for the role, protects the deduction.

What you need to document

None of this holds up on the strength of the numbers alone. Each item below is what turns a correct position into one that survives being questioned.

A contemporaneous QSBS file, built at issuance

There is no election or form filed when qualifying stock is issued; the exclusion is claimed later, on Form 8949 and Schedule D, when the stock is sold. That means the proof has to be assembled years before it is used: the gross-assets computation at each issuance date, confirmation that C status was continuous, and each shareholder's acquisition date and basis tracked lot by lot, since the exclusion percentage depends on exactly when each block of stock was acquired.

Board approval and market data for compensation

A board resolution setting the owner-employee's salary, backed by comparable compensation data for the role. This is what stands behind the deduction if the amount is ever questioned as a disguised dividend.

A specific, written business reason for retained earnings

Board minutes describing definite and feasible plans for the cash, tied to an actual working-capital calculation for the operating cycle. A general statement that the corporation might need the money someday is not the same record.

Where it goes wrong

Double taxation is not a risk that shows up on examination; it is the built-in cost of the structure, and the failure is choosing a C corporation for a business that distributes its profit with no Section 1202 exit in view. Two further penalty taxes exist to stop a C corporation from using its lower rate to defer or convert tax that was never going to reach the shareholder level.

The accumulated earnings tax

A 20 percent penalty, on top of the regular corporate tax, on income a corporation lets accumulate beyond the reasonable needs of the business. An accumulated earnings credit floors the exposure at the greater of those needs or $250,000 of accumulated earnings and profits, reduced to $150,000 for a corporation whose principal function is health, law, engineering, architecture, accounting, actuarial science, the performing arts, or consulting. Above that floor, the defense is a documented, specific, feasible business reason for the cash and a working-capital calculation covering the operating cycle, a formula tracing back to a single Tax Court case, Bardahl Manufacturing.

The personal holding company tax

Also a 20 percent penalty, on top of the regular tax, on undistributed passive income once two tests are both met: at least 60 percent of adjusted ordinary gross income is personal holding company income (dividends, interest, royalties, or certain rents), and more than 50 percent of the stock, by value, is owned by five or fewer individuals at any point during the back half of the year. A closely held investment or holding corporation is the usual target. The two penalty taxes are mutually exclusive; a personal holding company is exempt from the accumulated earnings tax by statute, and a deficiency dividend can cure this tax after the fact, though not the interest on the underpayment.

The NIIT cost of converting for QSBS

An S corporation owner who materially participates gets an overlooked benefit on the way out: the net investment income tax on gain from disposing of the interest reaches only the slice attributable to property the entity does not use in its active trade or business, not the whole gain. That limitation applies to a partnership or S corporation interest specifically and has no counterpart for C corporation stock, which is fully treated as net investment income on disposition. Converting an S corporation to a C corporation purely to access Section 1202 gives up that limitation; on the slice of gain that would not have been excluded anyway, the applicable rate moves from roughly 20 percent to 23.8 percent, a cost a model built around one blended capital-gains rate will not show.

The recurring mistakes

• Compensation set to maximize the deduction rather than reflect the job, inviting the disguised-dividend challenge.
• Retained cash with no documented business reason, precisely what the accumulated earnings tax targets.
• Assuming Section 1202 applies to a service business, when it generally does not, regardless of size or structure.
• Missing the QSBS asset ceiling or the original-issuance requirement, or running the holding-period clock from the wrong date.
• A stock redemption too close to the issuance date, which the statute treats as disqualifying.

A business that drifted into C status for reasons that no longer apply, and now distributes what it earns every year, is not stuck. Converting out has its own timing traps, covered separately in C corp to S corp late election.

A situation where this comes up

The case where a C corporation earns its place is a founder building a product company, still years from any exit, reinvesting nearly everything the business makes. Nothing about it costs that founder anything today beyond the 21 percent entity-level tax on income the business was going to keep anyway. If the stock is eventually sold after clearing the holding period, Section 1202 can turn a capital-gains tax bill into a very small one, which is exactly why the QSBS file has to be built at issuance rather than assembled later when someone finally asks for it.

The case I try to head off is different: a business advised into a C corporation years ago for a reason that no longer applies, run by an owner who takes out most of what it earns every year to live on. Nobody modeled the double tax against a pass-through at the time, and the entity choice was never revisited. That business pays the full cost of the structure with none of the offsetting benefit, year after year. The fix is simply recognizing that the original decision no longer fits the current facts.

The third pattern is the one that looks the most sophisticated and is the easiest to get wrong: converting an S corporation to a C corporation specifically to put Section 1202 in play. That can be the right call for a business genuinely headed toward a sale of stock rather than assets. It is the wrong call when nobody has weighed what the conversion gives up, including the NIIT treatment the S corporation had and the C corporation will not, against a QSBS benefit that is still years away.