A stock sale is the sale of a corporation accomplished by transferring its shares from the existing shareholders directly to a buyer, so the company itself keeps operating with the same legal identity, the same contracts, and the same liabilities. The sellers are the individual shareholders, not the business. The buyer, once enough shares have changed hands, controls the corporation exactly as it stood the moment before closing.
That single feature drives almost everything else about how these deals are negotiated, diligenced, and taxed.
Why Sellers and Buyers Pick Different Structures
Sellers generally push for stock sales. The proceeds flow to them as capital gains, and they avoid the double taxation that hits when a corporation sells appreciated assets and then distributes the cash to its owners.
Buyers often prefer an asset sale, where they can choose which assets and liabilities to take and write up the value of what they acquire for fresh depreciation. In a stock sale they get no such write-up by default, and they inherit the whole entity. The tension between those two preferences is what most deal negotiation is really about.
What the Buyer Inherits
Because the corporation survives intact, everything inside it comes along. Existing debts, leases, vendor contracts, and employment agreements stay in place. Pending lawsuits and regulatory investigations don’t disappear at closing. Contingent liabilities like warranty exposure or environmental cleanup from past operations travel with the shares. The financial and legal condition of the business is inseparable from the stock being purchased.
A buyer who misses a tax dispute or an unresolved claim can’t leave it behind after closing. The claim belongs to the corporation, and the corporation now belongs to the buyer.
Due Diligence Before Closing
That exposure is the reason diligence in a stock sale runs deeper than in an asset deal. On the financial side, the buyer reviews audited and unaudited financial statements, correspondence with outside auditors, projected budgets and cash flow, and a list of any liabilities not captured on the most recent balance sheet.
Tax records get their own pass. Buyers typically request federal, state, and local returns for at least the three most recent closed tax years and all open years, plus documentation of any past or ongoing audits and a schedule of every jurisdiction where the company files. That schedule is often how back-tax exposure surfaces.
On the legal side, the buyer works through outstanding loans, security agreements, guarantees, lines of credit, and any pending or threatened litigation, including government investigations.
What Keeps Running After Closing
One practical upside of a stock sale is continuity. The corporation’s Employer Identification Number stays the same, because the IRS does not require a new EIN when corporate ownership changes hands.1Internal Revenue Service. When to Get a New EIN Operating licenses and permits generally remain valid because the entity holding them hasn’t changed. Contracts continue as drafted, since the corporation, not the shareholders, is the contracting party.
Continuity isn’t automatic for every relationship, though. Many commercial contracts include change-of-control provisions that treat a transfer of majority ownership like an assignment. When one of those clauses exists, the counterparty can consent, renegotiate, or terminate once the sale closes. Buyers need to flag every material contract with that language early. If a key customer or supplier agreement requires third-party consent, that consent usually becomes a condition to closing.
Key Documents
Preparation starts with the capitalization table, which lists every shareholder, their share count, and the class of stock they hold. Sellers need to locate the original stock certificates to prove ownership; if one has been lost, the shareholder files an affidavit and typically buys an indemnity bond to protect the corporation against the certificate resurfacing later.2U.S. Securities and Exchange Commission. Lost or Stolen Stock Certificates
The Stock Purchase Agreement is the central contract. It sets the price per share, the representations and warranties about the company’s financial and legal condition, indemnification obligations, and the conditions each side must meet before closing. Representations and warranties commonly survive six months to a year after closing, during which the buyer can bring indemnification claims for breaches.
Corporate resolutions passed by the board formally authorize the sale under the bylaws. Updated financials and recent tax returns back up what the purchase agreement says. Organizing the records into a clean data room before negotiations start tends to speed things up and build buyer confidence.
Minority Shareholders, Drag-Along, and Tag-Along Rights
Because each shareholder has to agree to transfer their own shares, a stock sale can be held up by owners who don’t want to sell. Most shareholder agreements address this with a drag-along provision, which lets majority shareholders force minority holders to sell on the same terms. That prevents a small block from blocking a deal the majority supports.
Tag-along rights run the other direction. They let minority holders join a sale on the same terms offered to the majority, so a controlling shareholder can’t negotiate a premium price and leave smaller holders stuck with an illiquid stake under new management. Both provisions get drafted into the shareholder agreement long before any sale is on the table.
Closing the Transaction
Closing day is built around signing the Stock Purchase Agreement and its related documents. Electronic signatures are enforceable for these transactions under the Electronic Signatures in Global and National Commerce Act, which bars denying a contract effect solely because it was signed electronically.3Office of the Law Revision Counsel. 15 USC Chapter 96 – Electronic Signatures in Global and National Commerce Once signatures are in place, the buyer wires the price.
A slice of the purchase price is usually deposited into escrow rather than paid straight to the sellers. Those funds sit as a pool for indemnification claims if the buyer later discovers a breach of the seller’s representations and warranties. Escrow periods commonly run six to eighteen months, and the amount held back is part of the negotiation.
After funds clear, old stock certificates are cancelled in the corporate records, new certificates are issued to the buyer, and the internal stock ledger is updated with the new owner and the transfer date. At that point, the buyer controls the corporation.
Securities Law Applies Even When the Deal Is Private
A private stock sale is still a transfer of securities, so federal and state securities laws apply. Most private company deals rely on exemptions from SEC registration. The most common is the private placement exemption for transactions not involving a public offering; Regulation D allows sales to an unlimited number of accredited investors, with sales to non-accredited investors capped at 35 and carrying extra disclosure requirements. State blue sky laws add another layer; some federal exemptions, like Rule 506(b) and Rule 506(c), preempt state registration, but others do not.4SEC.gov. Frequently Asked Questions About Exempt Offerings Confirm the exemption at both levels before shares move.
Tax Rules for Sellers
Capital Gains on the Sale
The seller’s gain is the difference between the sale price and their original cost basis in the shares. Stock held as an investment is a capital asset under the tax code, so the gain is taxed at capital gains rates rather than as ordinary income.5Office of the Law Revision Counsel. 26 US Code 1221 – Capital Asset Defined For shares held longer than a year, the long-term capital gains brackets for 2026 are:
- 0% on taxable income up to $49,450 for single filers, $98,900 for married filing jointly, or $66,200 for head of household.
- 15% on taxable income above the 0% threshold up to $545,500 for single filers, $613,700 for married filing jointly, $579,600 for head of household, or $306,850 for married filing separately.
- 20% on taxable income above the 15% ceiling.6Internal Revenue Service. Revenue Procedure 2025-32
Shares held a year or less are taxed at short-term rates, which match the seller’s ordinary income bracket.
The 3.8% Net Investment Income Tax
Higher-income sellers pay an additional 3.8% tax on net investment income, and capital gains from a stock sale are included. The surtax applies when modified adjusted gross income exceeds $200,000 for single filers, $250,000 for married filing jointly, or $125,000 for married filing separately.7Office of the Law Revision Counsel. 26 US Code 1411 – Imposition of Tax Those thresholds are not indexed for inflation. Most sellers in a business stock sale will clear them, which puts the effective top rate on long-term gain at 23.8%.
Qualified Small Business Stock Exclusion
Sellers of stock in a qualifying small business may exclude part or all of the gain under Section 1202. For stock issued after July 4, 2025, the exclusion phases in with holding period: 50% of the gain is excluded after three years, 75% after four years, and 100% after five years.8Office of the Law Revision Counsel. 26 USC 1202 – Partial Exclusion for Gain From Certain Small Business Stock For stock issued between September 2010 and July 4, 2025, the full 100% exclusion requires more than five years of holding.
To qualify, the company must have been a domestic C corporation with aggregate gross assets of $75 million or less at the time the stock was issued ($50 million for stock issued before July 4, 2025). It must use at least 80% of its assets in a qualifying trade or business, which excludes fields like finance, law, accounting, and hospitality. The seller must be an individual or pass-through entity, not a C corporation, and must have acquired the stock directly from the issuing company in exchange for cash, property, or services.8Office of the Law Revision Counsel. 26 USC 1202 – Partial Exclusion for Gain From Certain Small Business Stock For stock issued after July 4, 2025, the maximum excludable gain per issuer is the greater of $15 million or ten times the seller’s adjusted basis in the stock.
Installment Sales
When the buyer pays over time, the seller can use the installment method to spread the taxable gain across the years payments are received, with the gain recognized each year proportional to the ratio of profit to total contract price. That can meaningfully cut the tax hit in the year of sale by keeping the seller in lower brackets. Installment treatment is not available for stock traded on an established securities market; there, the full gain is recognized in the year of sale.9Office of the Law Revision Counsel. 26 US Code 453 – Installment Method
Tax Rules for Buyers
The buyer’s cost basis in the acquired shares equals what they paid. The underlying assets inside the corporation, though, keep their existing tax basis and depreciation schedules. Equipment the company has been depreciating for five years continues on that same schedule, even though the buyer effectively paid current market value for the business. There is no automatic step-up in the basis of the company’s assets.
A Section 338(h)(10) election can change that. When the target was a member of a consolidated group or is an S corporation, the buyer and seller can jointly elect to treat the stock purchase as if the target sold all its assets at fair market value and then bought them back.10Office of the Law Revision Counsel. 26 USC 338 – Certain Stock Purchases Treated as Asset Acquisitions The buyer gets a stepped-up basis in the target’s assets and fresh depreciation and amortization deductions going forward. The trade-off is that the target recognizes gain on the deemed asset sale, though in a consolidated group the selling parent can offset that against the stock sale proceeds. The election is common in S corporation acquisitions, but it requires both sides to sign on, because the tax burden shifts between them.