Quick Answer

Selling an S Corp to a C Corp triggers a complex chain of tax consequences that can cost you $50,000 to $200,000+ if you choose the wrong deal structure. The buyer wants an asset purchase to step up basis and claim 100% bonus depreciation under OBBBA. The seller wants a stock sale to pay one layer of capital gains tax at 23.8% federally. The compromise usually involves an IRC Section 338(h)(10) election, which treats a stock sale as an asset sale for tax purposes, giving both parties what they want. But California throws a wrench into the equation with its own conformity rules, and the wrong move on day one can lock you into a six-figure tax bill you never saw coming.

This information is current as of March 25, 2026. Tax laws change frequently. Verify updates with the IRS or FTB if reading this later.

Why Selling an S Corp to a C Corp Creates a Unique Tax Problem

Most business owners think a sale is a sale. Hand over the keys, deposit the check, pay capital gains, done. But when you are selling an S Corp to a C Corp, you are merging two entirely different tax universes, and the collision creates consequences that do not exist in any other type of business sale.

An S Corp is a pass-through entity. Profits and losses flow to shareholders on Schedule K-1. There is no entity-level federal tax (except in narrow cases like built-in gains or excess passive income). A C Corp, on the other hand, pays its own corporate tax at 21% under IRC Section 11, and then shareholders pay again when dividends are distributed. That is the classic double-taxation structure.

When a C Corp acquires your S Corp, the buyer’s tax posture directly affects how much you, the seller, actually keep. If the buyer cannot step up the basis in your company’s assets, they pay more tax over time, which means they offer you a lower purchase price. If you agree to an asset sale to give the buyer that step-up, you may face ordinary income rates on certain asset categories instead of the favorable 20% long-term capital gains rate.

This tension between buyer and seller is the central negotiation in every S Corp acquisition by a C Corp. The deal structure you choose will determine your effective tax rate on the entire transaction. Choose correctly, and you keep 75 to 80 cents of every dollar. Choose wrong, and you keep 55 cents or less.

The Three Deal Structures You Need to Understand

Every S Corp sale to a C Corp falls into one of three categories:

1. Straight Stock Sale: The buyer purchases your shares. You pay one layer of capital gains tax (20% federal + 3.8% NIIT + state). The buyer gets no step-up in asset basis, which means lower depreciation deductions going forward. This makes the company less valuable to the buyer, so they typically lower their offer price.
2. Straight Asset Sale: The S Corp sells its individual assets (equipment, inventory, goodwill, customer lists). You get hit with a blended tax rate because each asset class is taxed differently. Inventory and accounts receivable generate ordinary income. Equipment triggers depreciation recapture under IRC Section 1245. Goodwill gets favorable capital gains treatment. The buyer gets a full step-up in basis and can claim 100% bonus depreciation on qualifying assets.
3. Stock Sale with Section 338(h)(10) Election: The buyer purchases your stock, but both parties jointly elect to treat the transaction as an asset sale for tax purposes. This gives the buyer the step-up they want while keeping the legal simplicity of a stock transaction. This is the most common structure when a C Corp acquires an S Corp, and it is where the real tax planning happens.

The Section 338(h)(10) Election: How It Works and Why It Matters When Selling an S Corp to a C Corp

Section 338(h)(10) of the Internal Revenue Code is the single most important provision in any S Corp sale to a C Corp. It allows the buyer and seller to jointly elect to treat a stock purchase as if it were an asset purchase. The election is made on IRS Form 8023, and it must be filed by the 15th day of the 9th month following the month of the acquisition.

Here is what happens mechanically when you make this election:

• The S Corp is treated as having sold all of its assets at fair market value on the acquisition date
• The gain from that deemed asset sale flows through to you on your final K-1
• The S Corp is then treated as a new corporation that purchased those assets at the stepped-up fair market value
• The buyer gets full basis step-up and can claim 100% bonus depreciation on qualifying assets under the permanent OBBBA rules

For a deeper dive into how S Corp tax mechanics interact with these elections, our comprehensive S Corp tax strategy guide breaks down the foundational rules you need to understand before structuring any sale.

The Purchase Price Allocation Problem

When you make the 338(h)(10) election, the total purchase price must be allocated across seven asset classes under IRC Section 1060 and the residual method described in IRS Publication 544. This allocation directly determines your tax bill because different asset classes are taxed at different rates:

• Class I (Cash and equivalents): No gain or loss
• Class II (Actively traded securities): Capital gains rates
• Class III (Accounts receivable, inventory): Ordinary income rates (up to 37%)
• Class IV (Stock in trade): Ordinary income rates
• Class V (Equipment, furniture, vehicles): Depreciation recapture at ordinary rates under Section 1245, remainder at capital gains
• Class VI (Section 197 intangibles): Capital gains rates (15-year amortizable)
• Class VII (Goodwill and going concern value): Capital gains rates

The negotiation over purchase price allocation is where sellers lose the most money. The buyer wants to allocate as much as possible to Classes III through V because those assets generate faster deductions. The seller wants maximum allocation to Classes VI and VII because goodwill is taxed at favorable long-term capital gains rates. This is not a minor detail. On a $2 million deal, shifting $300,000 from goodwill to equipment can cost you an additional $51,000 in taxes.

Key Takeaway: The purchase price allocation in a 338(h)(10) election is a zero-sum negotiation between buyer and seller. Every dollar allocated to ordinary income assets saves the buyer money and costs you money. Get this wrong and the deal that looked like $2 million nets you $1.4 million instead of $1.6 million.

California’s Tax Traps When Selling an S Corp to a C Corp

If your S Corp operates in California, you face a second layer of complexity that most advisors outside the state fail to address. California conforms to the federal 338(h)(10) election, but the state adds its own penalties through several mechanisms that can erode your proceeds by $15,000 to $40,000 on a mid-sized deal.

Many business owners operating in California underestimate how aggressively the FTB treats entity-level transactions. Here are the four California traps to watch for:

Trap 1: The 1.5% S Corp Franchise Tax on Deemed Asset Sale Gain

California imposes a 1.5% franchise tax on S Corp net income under Revenue and Taxation Code Section 23802(b). When you make the 338(h)(10) election, the deemed asset sale gain flows through the S Corp before reaching you as a shareholder. That means the S Corp itself owes 1.5% on the entire gain. On a $1.5 million gain, that is $22,500 in entity-level tax that does not exist at the federal level.

Trap 2: California’s 13.3% Top Individual Rate

California does not offer a preferential rate for capital gains. All capital gains are taxed as ordinary income at the state level, with the top marginal rate hitting 13.3% for income above $1 million. Combined with the 20% federal capital gains rate and 3.8% NIIT, your blended effective rate on the goodwill portion of the sale reaches approximately 37.1%. On the ordinary income portion (inventory, receivables, depreciation recapture), your combined rate can exceed 50%.

Trap 3: The Built-in Gains Tax Trap for Recent Converters

If your S Corp was previously a C Corp and you converted within the last five years, you may owe the federal built-in gains (BIG) tax under IRC Section 1374. This imposes a 21% corporate-level tax on any gain attributable to assets that had built-in appreciation at the time of the S election. California adds its own 1.5% BIG tax on top. For a company that converted from C Corp to S Corp three years ago with $500,000 in built-in gain, that is $112,500 in BIG tax ($105,000 federal + $7,500 California) that the shareholders must absorb before they see a dime of the sale proceeds.

Trap 4: The AB 150 PTE Election Timing Problem

California’s AB 150 Pass-Through Entity (PTE) elective tax allows S Corps to pay a 9.3% entity-level tax and generate a dollar-for-dollar credit on the shareholders’ personal returns. This effectively converts a non-deductible state tax into a deductible business expense, generating significant federal savings. But here is the problem: the PTE election must be made for the full tax year. If you sell your S Corp mid-year, the PTE election for the short-year return creates complications that most tax preparers do not handle correctly. Miss this, and you lose $3,000 to $15,000 in AB 150 savings on your final year of S Corp ownership.

Want to see how these combined rates affect your actual take-home? Run your numbers through this small business tax calculator to estimate your total liability before and after the sale.

The Five Costly Mistakes Sellers Make When Selling an S Corp to a C Corp

Mistake 1: Ignoring the Purchase Price Allocation Until Closing

Too many sellers treat the purchase price allocation as an afterthought. They negotiate the total price, sign the letter of intent, and then discover during due diligence that the buyer’s proposed allocation shifts $400,000 from goodwill into inventory and equipment. By that point, you have already committed to the deal terms, and pushing back on allocation feels like renegotiating the price. Smart sellers negotiate the allocation simultaneously with the purchase price. Lock it down in the LOI, not the closing documents.

Mistake 2: Failing to Run the 338(h)(10) vs. Straight Stock Sale Comparison

The 338(h)(10) election is not always the right answer. In some cases, a straight stock sale produces a better after-tax result for the seller, especially when the company has significant ordinary income assets (inventory, receivables) and limited goodwill. The only way to know is to run both scenarios side-by-side with actual numbers. If your tax advisor has not modeled both structures with your specific asset mix, you are guessing with six figures on the line.

Mistake 3: Overlooking the Installment Sale Option

If the buyer is paying you over time (seller financing, earnouts, or installment notes), you may qualify for installment sale treatment under IRC Section 453. This lets you spread the gain recognition over the payment period, potentially keeping you in lower tax brackets in each year. However, installment sale treatment is not available for the ordinary income portion of a 338(h)(10) deemed asset sale. You must recognize all ordinary income in the year of sale, even if you have not received the cash yet. This catches sellers off guard when they owe $200,000 in taxes but have only received $100,000 in year-one payments.

Mistake 4: Not Adjusting Shareholder Basis Before the Sale

Your S Corp stock basis determines how much of the sale proceeds are taxable. If your basis is understated because you failed to track annual income pass-throughs, distributions, and losses properly, you will overpay taxes on the sale. Before any transaction, reconstruct your basis from inception. This means going back to your original capital contribution and tracking every K-1 item, every distribution, and every debt adjustment year by year. KDA regularly finds $30,000 to $80,000 in basis errors during pre-sale reviews.

Mistake 5: Forgetting the Final S Corp Return and K-1 Deadlines

When you sell your S Corp, you must file a final Form 1120-S and issue final Schedule K-1s to all shareholders. The return is due on the 15th day of the 3rd month after the sale closes. If the sale closes on June 30, the final return is due September 15. California requires a corresponding final Form 100S. Miss these deadlines, and the IRS imposes a penalty of $235 per shareholder per month (2026 rate), while the FTB adds its own late-filing penalties. For a three-shareholder S Corp that files six months late, that is $4,230 in avoidable federal penalties alone.

Our tax planning services include pre-sale transaction modeling that catches these mistakes before they cost you money, not after.

KDA Case Study: S Corp Manufacturing Owner Saves $127,000 on $1.8 Million Sale to a C Corp Buyer

Marcus owned a precision machining S Corp in Ontario, California, with $1.8 million in annual revenue and $420,000 in net profit. After eight years, a publicly traded C Corp offered to acquire his company for $2.1 million. Marcus’s previous accountant prepared a basic tax projection showing $518,000 in combined federal and California taxes on the deal, leaving Marcus with approximately $1.58 million.

KDA reviewed the proposed deal structure and found three critical problems. First, the buyer’s purchase price allocation placed $620,000 in equipment and inventory (taxed at ordinary income rates up to 50.3% combined) and only $890,000 in goodwill. Second, Marcus had $94,000 in unrecognized shareholder basis from accumulated S Corp income he had never distributed. Third, no one had modeled the AB 150 PTE election for the short tax year.

KDA restructured the transaction as follows: we negotiated the purchase price allocation to shift $180,000 from equipment to goodwill, saving Marcus $30,600 in ordinary income tax. We reconstructed his shareholder basis from inception, increasing it by $94,000 and reducing his taxable gain dollar-for-dollar, saving $35,200 in capital gains and NIIT. We filed the AB 150 PTE election for the short year, generating a $12,800 federal deduction through the state tax credit mechanism. And we structured the earnout component as an installment sale under IRC Section 453, deferring $48,400 in capital gains tax to years two and three when Marcus’s income would be lower.

Total first-year tax savings: $127,000. Marcus paid KDA $8,200 for the engagement, producing a 15.5x ROI in year one. His effective tax rate on the deal dropped from 24.7% to 18.6%, putting an additional $127,000 in his pocket on the same $2.1 million purchase price.

Ready to see how we can help you? Explore more success stories on our case studies page to discover proven strategies that have saved our clients thousands in taxes.

Should You Make the 338(h)(10) Election? A Decision Framework

The decision to elect 338(h)(10) treatment when selling an S Corp to a C Corp depends on five factors. Run through this checklist before committing to any deal structure:

Elect 338(h)(10) if:

• Goodwill and intangibles represent 60%+ of total enterprise value (favorable capital gains treatment on the bulk of the gain)
• The buyer offers a higher purchase price in exchange for the step-up (quantify this: a 5 to 10% price increase can offset your additional tax cost)
• The company has minimal inventory and accounts receivable (less ordinary income exposure)
• The company was always an S Corp (no BIG tax risk from a prior C Corp conversion)
• You want clean legal separation with no successor liability

Skip the 338(h)(10) election if:

• Ordinary income assets (inventory, receivables, depreciation recapture) represent 40%+ of value
• The company has significant net operating loss carryforwards that would be wasted
• You converted from C Corp status within the last five years (BIG tax exposure)
• The buyer is not willing to increase the price to compensate for your higher tax cost
• You are in a state with no income tax and the California traps do not apply

The Price Adjustment Formula

A useful rule of thumb: the buyer should increase the purchase price by approximately 70 to 80% of the federal tax benefit they receive from the basis step-up. On a $2 million deal where the buyer gains $400,000 in year-one bonus depreciation deductions (saving $84,000 at 21% corporate rate), the seller should negotiate an additional $59,000 to $67,000 in purchase price. This compensates the seller for the higher blended tax rate created by the 338(h)(10) election while still leaving the buyer better off than a straight stock sale. If the buyer refuses to share the tax benefit, a straight stock sale may produce a better net result for you.

What If the Buyer Wants an Asset Purchase Instead of a 338(h)(10) Election?

Some C Corp buyers prefer a direct asset purchase over a stock purchase with a 338(h)(10) election. From the buyer’s perspective, the tax result is essentially the same: they get a full basis step-up in all acquired assets. But from the seller’s perspective, an asset purchase creates an additional layer of tax complexity.

In a direct asset purchase, the S Corp itself sells its assets and recognizes gain at the entity level. That gain flows through to you on your K-1. Then, when you liquidate the S Corp and distribute the remaining cash, you face a second potential taxable event on any difference between the liquidating distribution and your adjusted stock basis. In most cases, the math works out roughly the same as a 338(h)(10) election, but there are scenarios where the direct asset sale creates timing differences and state tax disparities that cost you money.

The bigger issue with a direct asset sale is contract assignment. The buyer must individually negotiate the assignment of every contract, lease, license, and permit held by the S Corp. In a stock purchase (even with a 338(h)(10) election), the legal entity continues to exist, so contracts typically survive the transaction without requiring third-party consent. For companies with dozens of customer contracts, government permits, or real property leases, the stock purchase with 338(h)(10) election is almost always preferable because it avoids the assignment problem entirely.

Will Selling an S Corp to a C Corp Trigger an Audit?

The IRS does not automatically audit S Corp sales, but certain elements of the transaction increase your audit risk significantly. The three biggest audit triggers are:

1. Inconsistent purchase price allocations: The buyer and seller must report the same allocation on their respective returns (Form 8594 for both parties). If the IRS sees different numbers, both returns get flagged. This happens more often than you would expect when buyer and seller use different accounting firms that do not coordinate.
2. Large goodwill allocations without supporting documentation: If 80% of your purchase price is allocated to goodwill, the IRS may challenge whether a formal valuation supports that allocation. Get a qualified appraisal before closing, not after.
3. Basis discrepancies on the final K-1: If the gain reported on your final K-1 does not reconcile with your stock basis and the Form 8594 allocation, the IRS computer matching system will flag the discrepancy. This is why reconstructing basis before the sale is not optional.

California’s FTB conducts its own review of S Corp sales, particularly when the AB 150 PTE election is involved in a short tax year. The FTB has been increasingly aggressive about challenging short-year PTE elections since 2024, so documentation of the election timing is critical.

Pro Tip: File Form 8594 (Asset Acquisition Statement) with your tax return for the year of sale, and keep a signed copy from both parties in your permanent records. If the IRS questions the allocation five years from now, this document is your first line of defense.

Frequently Asked Questions About Selling an S Corp to a C Corp

How Long Does the Tax Planning Process Take Before Closing?

Start the tax structuring process at least 90 days before your expected closing date. The shareholder basis reconstruction alone can take 30 to 45 days if your records are incomplete. The purchase price allocation negotiation typically runs parallel with due diligence, but you need your own tax model ready before the buyer presents their allocation. Rushing this process is how sellers leave $50,000 or more on the table.

Can I Defer the Entire Gain with a 1031 Exchange?

No. Section 1031 like-kind exchanges apply only to real property, not to stock or business assets sold in a 338(h)(10) transaction. If your S Corp owns real estate, you may be able to distribute the property to shareholders before the sale and then execute a 1031 exchange on just the real estate component. But this requires careful pre-sale planning and must be completed before the stock purchase agreement is signed. Attempting this after closing is too late.

What Happens to My S Corp’s Unused Losses After the Sale?

Any suspended passive activity losses or at-risk limitations that you carried on your personal return are released in full in the year of sale. This means if you had $40,000 in suspended passive losses from the S Corp, those losses become deductible against the sale gain, reducing your taxable gain dollar-for-dollar. Make sure your tax preparer captures these on your final return, because this deduction is frequently missed.

Do I Need a Separate Valuation for the 338(h)(10) Election?

While a formal valuation is not technically required to make the election, it is practically essential. The purchase price allocation must be defensible under IRS audit. A qualified appraisal from a credentialed business valuator (ASA or ABV designation) costs $5,000 to $15,000 but protects allocations worth $50,000 or more in tax savings. The cost of the appraisal is deductible as a transaction expense.

Book Your Pre-Sale Tax Strategy Session

If you are considering selling your S Corp to a C Corp buyer, the deal structure you choose today will determine whether you keep 75 cents or 55 cents of every dollar. That gap represents tens of thousands, sometimes hundreds of thousands, in taxes that are entirely within your control. Book a personalized consultation with our strategy team and walk away with a clear, modeled comparison of your deal options before you sign anything. Click here to book your pre-sale consultation now.