A $500 million sale can leave shareholders with two very different outcomes. In one version, target shareholders write checks to the IRS the moment the deal closes. In the other, they walk away holding acquirer stock with the same basis they had before — no current tax, gain deferred indefinitely. The difference between those two outcomes is rarely about the price or the strategy. It is almost always about whether the deal is structured to qualify as a "reorganization" under Internal Revenue Code Section 368.
Section 368 is the single most important set of rules in M&A tax. It defines seven separate flavors of reorganization (Types A through G) that let a corporation be acquired, restructured, divided, or repaired in bankruptcy without triggering corporate-level or shareholder-level tax. Miss a single requirement and the entire deal becomes a fully taxable sale at fair market value. This guide walks through the major types, the doctrinal tests every reorganization must satisfy, the role of "boot," and the triangular merger structures that dominate modern dealmaking.
Why Section 368 Exists
Without Section 368, every corporate combination would be a taxable disposition. A shareholder swapping target stock for acquirer stock would realize gain on the appreciation in their target shares, even though they ended up holding a different paper claim on essentially the same business. Congress recognized that some transactions are economic "readjustments of continuing interests" rather than genuine cash-outs. The reorganization rules let those transactions defer tax — gain is preserved in the form of carryover basis and shows up later when shareholders eventually sell the acquirer stock for cash.
Three principles run through the entire statute:
- Deferral, not exemption. Built-in gain is preserved, not eliminated. Target shareholders take a carryover basis in the acquirer stock they receive, and the acquirer takes a carryover basis in target assets.
- Continuity over change. Shareholders and businesses must be substantially the same on both sides of the transaction.
- All or nothing. If a deal fails even one Section 368 requirement, the entire transaction is taxable, not just the offending piece.
The Four Universal Doctrinal Tests
Before any deal can qualify under one of the seven types, it must satisfy four overarching tests that the IRS and courts apply across the board. Skipping any of them collapses the reorganization.
1. Continuity of Interest (COI)
Target shareholders must retain a meaningful equity stake in the post-deal enterprise. The IRS administratively treats COI as satisfied when at least 40% of the consideration paid to target shareholders consists of acquirer stock (any class — voting or nonvoting will do for COI purposes, though specific types impose stricter requirements). Cash, debt, and other non-stock consideration is fine up to roughly 60%.
The 40% threshold is measured by value, signing-date pricing rules can lock it in, and pre-arranged post-closing sales of the new stock can blow it up. If a fund agrees in advance to dump the acquirer shares the day after closing, COI is at risk.
2. Continuity of Business Enterprise (COBE)
The acquirer must either continue the target's historic line of business or use a significant portion of the target's historic business assets in some business after the deal. Buying a target and immediately liquidating it for the cash on its balance sheet will fail COBE. Buying a target and folding its operations into a similar division will not.
3. Business Purpose
There must be a non-tax business reason for the transaction. Most strategic deals satisfy this almost automatically — synergies, market expansion, technology acquisition. But pure tax-motivated reshufflings (especially divisive D reorganizations) draw heavier scrutiny here.
4. Plan of Reorganization
The transaction must be carried out pursuant to a formal written plan adopted by the boards of the corporations involved. Practitioners typically embed this language inside the merger agreement.
A related doctrine, the step transaction doctrine, lets the IRS collapse multiple steps into one to test substance over form. If you spin off a subsidiary and then immediately sell it under a pre-arranged plan, the steps may be combined and the reorganization disallowed.
Type A: Statutory Mergers and Consolidations
A Type A is the workhorse of M&A: a state-law statutory merger where one corporation legally combines into another, the target ceases to exist, and target shareholders receive consideration from the acquirer. Section 368(a)(1)(A) imposes no statutory consideration limits — only the COI doctrine's 40% stock floor applies. That makes Type A the most flexible direct-merger structure available, allowing up to roughly 60% cash, debt, or other property.
Type A's downside is that the acquirer steps directly into the target's assets and liabilities — including unknown contingent ones — and certain non-transferable contracts and licenses can be lost in the legal combination.
Type B: Stock-for-Stock Acquisitions
A Type B is a pure paper deal. The acquirer issues only its own voting stock in exchange for target stock, and immediately after the exchange the acquirer must hold at least 80% of the voting power and 80% of every other class of target stock. Cash and other "boot" are not allowed at all — solely-for-voting-stock is the rule.
The target survives as a wholly owned subsidiary of the acquirer, which is convenient when contracts, licenses, or regulatory approvals would be jeopardized by a merger that extinguishes the target. The cost is rigidity: even a small cash component (a fractional-share cash payment is the rare exception) can disqualify the deal.
Type C: Asset Acquisitions for Stock
A Type C is a stock-for-assets swap. The acquirer takes "substantially all" of the target's assets in exchange for acquirer voting stock, and the target then liquidates and distributes the stock (and any boot) to its shareholders. The IRS interprets "substantially all" as at least 70% of gross assets and 90% of net assets by fair market value.
Boot is permitted but limited: at least 80% of the value of all target assets acquired must be paid for in voting stock (the so-called "boot relaxation rule"), and liabilities the acquirer assumes count against that 80% if any cash boot is also used. Type C is useful when the acquirer wants assets (not the legal entity), but the tighter consideration mix and the mandatory target liquidation make it less common than triangular structures.
Triangular Mergers: The Modern Default
Direct A, B, and C deals are textbook but rarely used in practice. Most strategic transactions are structured as triangular mergers that drop a new subsidiary between the parent acquirer and the target. That extra entity provides a liability shield — the parent's other assets stay insulated from anything inherited from the target.
Forward Triangular Merger — Section 368(a)(2)(D)
The acquirer forms a new merger subsidiary, drops parent stock into it, and the target merges into the subsidiary. The subsidiary survives holding the target's assets, and target shareholders receive parent stock plus permitted boot. To qualify:
- The subsidiary must acquire "substantially all" of the target's properties.
- Only parent stock (no subsidiary stock) may be used as consideration.
- COI's 40% floor applies — meaning up to ~60% boot is allowed, far more flexible than a Type B's all-stock requirement.
Reverse Triangular Merger — Section 368(a)(2)(E)
The merger subsidiary merges into the target, the target survives, and target shareholders surrender their stock for parent stock plus boot. To qualify:
- The surviving target must hold substantially all the properties of both the target and the merger subsidiary.
- Target shareholders must exchange stock constituting control (80% of voting power and 80% of each nonvoting class) for parent voting stock.
The reverse triangular is the favored structure when the target's contracts, licenses, or regulatory authorizations are valuable and non-transferable — the target legally survives intact, so those rights are preserved. The price is a stricter consideration mix: at least 80% of the deal must be voting parent stock.
Type D: Acquisitive and Divisive
A Type D either consolidates a controlled group (acquisitive D) or splits a corporation into pieces (divisive D — the home of spin-offs, split-offs, and split-ups). Divisive Ds operate hand-in-hand with Section 355, which lets a parent distribute a controlled subsidiary's stock to its shareholders tax-free if both businesses have been actively conducted for five years, the distribution has a real business purpose, and continuity tests are met.
A classic example: a manufacturing company that also runs a software product line spins the software business into a new corporation and distributes those shares pro rata to existing shareholders. Done correctly, no gain is recognized at either the corporate or shareholder level.
Type E, F, and G: The Housekeeping Reorganizations
- Type E — Recapitalizations. The corporation reshuffles its own capital structure: exchanging preferred for common, swapping old debt for new stock, or modifying outstanding securities. No second corporation is required.
- Type F — Mere Changes. A "change in identity, form, or place of organization" — most commonly a state-of-incorporation change (Delaware reincorporation is the textbook case) or a holding-company formation.
- Type G — Insolvency. Reorganizations executed under Title 11 or similar federal/state bankruptcy proceedings. Provides essential relief so a restructuring debtor isn't crushed by additional tax on the workout itself.
The Mechanics of Boot
"Boot" is everything paid to target shareholders that is not qualifying acquirer stock — cash, notes, real property, securities of a third party. Boot is the lever that lets dealmakers add cash to a stock-heavy structure, but it carries direct shareholder-level tax consequences.
The basic rules:
- Recognized gain is the lesser of realized gain or boot received. A shareholder with $100 basis in target stock who receives $300 of acquirer stock plus $50 cash has a realized gain of $250 ($350 − $100) and recognizes $50 of gain (the boot amount).
- No loss is recognized, even if the shareholder is underwater. Losses in a reorganization are simply lost.
- Character follows the underlying gain — typically capital gain, though the dividend rules of Section 356(a)(2) can recharacterize boot as a dividend when the exchange has the effect of a distribution.
- Carryover basis with adjustments. New stock takes a basis equal to old basis, decreased by boot received and increased by gain recognized.
Common Failure Modes
The fastest way to destroy a reorganization is to violate one of these:
- Pre-arranged stock sale by a major target shareholder — kills COI even if the deal documents show stock consideration.
- Excess boot in a forward triangular merger — staying below the 40% stock floor by value drops the deal out of Type A/(2)(D) eligibility.
- Liquidation of target operations after closing in a way that fails COBE — buying a target and immediately gutting it converts the deal into a taxable disposition.
- Missing the "substantially all" test in a Type C or forward triangular — the IRS's 70% gross / 90% net safe harbor is not a statutory floor and aggressive structures get challenged.
- A pre-arranged divisive spin-and-sale that fails the step transaction doctrine — see Commissioner v. Court Holding Co. and decades of progeny.
Why Recordkeeping Matters in Reorganizations
A reorganization changes everything about a shareholder's basis position. Cost basis carries over, gets adjusted for boot and recognized gain, and follows the new stock for as long as the holder keeps it. Inside basis at the entity level follows similar carryover rules. Years later, when those shares are eventually sold, the IRS will expect a clean ledger of every step — original cost, every adjustment, every distribution.
For founders, fund managers, and operating shareholders, that means keeping organized financial records before, during, and after the transaction. Carryover-basis information that gets lost in a filing cabinet today is the audit problem of 2031. Pristine bookkeeping with transparent, auditable records is the difference between an easy basis defense and an expensive reconstruction project.
Practical Pre-Closing Checklist
- Confirm the four doctrinal tests in a formal tax opinion (or at least a tax memo) before signing.
- Lock in continuity-of-interest using signing-date stock value rules where possible.
- Run the deal through both forward and reverse triangular models — the answer often depends on which non-transferable contracts matter most.
- Identify all boot components, including assumed liabilities that may count as boot in a Type C.
- Verify each target shareholder's basis records before closing, so post-closing K-1s, 8937s, and shareholder communications are accurate.
- Plan post-closing integration so it does not gut the historic target business and trigger a COBE failure.
Keep Your Financial Records Audit-Ready Through Every Transaction
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