MAC / MAE Clauses

The MAC clause is the most heavily negotiated provision in a merger agreement and one of the least often successfully invoked. It exists to allocate the risk that the target's business deteriorates during the gap period.

Anatomy of a Typical MAC Definition

A MAC clause has two parts: a broad definition followed by a long list of carve-outs.

Definition (the trigger):

• "Any change, event, effect, or occurrence that has had, or would reasonably be expected to have, a material adverse effect on the business, results of operations, or financial condition of the company"

Carve-outs (things that do NOT count as a MAE):

• General economic conditions or industry conditions (unless they disproportionately impact the target)
• Changes in law or accounting standards
• Acts of war, terrorism, pandemics, and natural disasters
• The deal itself (announcement effects, customer reactions, employee departures)
• Failure to meet financial projections (though the underlying CAUSE of the miss may still qualify)

Most carve-outs have a disproportionate-impact override. If a recession hits the entire industry but hits the target much harder than its peers, the buyer can argue the disproportionate impact pierces the carve-out.

Think of it this way: The definition lets the buyer escape if the target falls apart. The carve-outs put the broader market risk back on the buyer. The disproportionate-impact override puts the target-specific portion of any market shock back on the seller.

Exam Tip: Gotchas

• Carve-outs do most of the work. General economic conditions, industry conditions, pandemics, and acts of war are excluded from MAE. The disproportionate-impact override pulls back only the seller-specific portion of any broader shock.
• MAC clauses are NOT symmetric. MAC protects the BUYER. The target relies on specific performance to force the buyer to close. Conflating the two is a frequent trap.

The Delaware Bar Is Extraordinarily High

For decades, no Delaware court found that a true MAC had occurred, even amid significant financial deterioration in target businesses.

Akorn v. Fresenius (2018) changed that record:

• The first (and as of 2026, still the only) Delaware Chancery decision to find a true MAE
• Affirmed by the Delaware Supreme Court in December 2018
• Vice Chancellor Travis Laster's opinion was the first time a Delaware court held that a seller suffered an MAE entitling the buyer to terminate

The facts of Akorn:

• Target's year-over-year revenue down approximately 25%
• Operating income down roughly 105% (a swing from positive to substantial negative)
• Earnings per share (EPS) down roughly 113%
• Widespread regulatory compliance failures at the company's manufacturing operations discovered post-signing
• Remediation cost estimated at nearly US$900 million to US$1 billion (roughly 20% of the deal value)

The court found TWO independent MAEs: a general financial MAE based on the operating collapse, and a separate regulatory MAE based on the compliance failures and the cost to fix them.

The standard the court applied:

• The change must be material AND durationally significant
• Durational significance is measured in years, not quarters
• A bad quarter does NOT satisfy the test
• The buyer bears the burden of proof

Exam Tip: Gotchas

• Akorn v. Fresenius (2018) is the singular Delaware precedent finding a MAE. Required a 25% revenue decline plus regulatory compliance collapse plus remediation costs near 20% of deal value. Cite Akorn as the only Delaware Chancery case to clear the bar.
• MAC requires materiality AND durational significance. A bad quarter is not enough. The change must be expected to persist for years. Trap answer choices may suggest a short-term decline triggers a walk-away.

Why MAC Is Rarely Invoked

Even after Akorn, MAC remains an outlier remedy:

• The buyer must show the change is durationally significant (long-lasting), not a short-term dip
• The buyer must show the change falls OUTSIDE the carve-outs (and any disproportionate-impact override does not pull the seller-specific portion back in)
• The target sues for specific performance to force closing, putting the buyer at risk of losing the litigation and being forced to close anyway at the original price
• In practice, most signed deals close even when business deteriorates; buyers prefer to renegotiate price or accept the deal as-is rather than risk a MAC litigation loss

The "Sandbagging" Wrinkle

A related question: can the buyer rely on a known breach at closing? The answer varies by state.

• "Pro-sandbagging" jurisdictions (Delaware default): the buyer can rely on a known breach if the contract is silent
• "Anti-sandbagging" jurisdictions: the buyer cannot rely on what it already knew
• Most merger agreements address the issue explicitly with a "pro-sandbagging" or "no-sandbagging" clause

Delaware is generally pro-buyer (sandbagging permitted unless the contract says otherwise), which gives a Delaware-buyer extra leverage if it learns of a breach before closing.

Exam Tip: Gotchas

• Sandbagging rules are state-specific and contract-driven. Delaware default is pro-sandbagging. Most agreements settle the issue explicitly with a "pro-sandbagging" or "no-sandbagging" clause.
• Specific performance is the target's primary remedy. When the buyer tries to walk on a MAC, the target sues for specific performance to force closing at the original price. Damages are usually not enough.