TL;DR: The Material Adverse Change clause is the most expensive exit ramp in corporate law. In the typical M&A deal, billions of dollars hinge on whether a deterioration in the target's business crosses the MAC threshold - yet courts have only once found a MAC to have occurred (Akorn v. Fresenius, 2018). That means buyers drafting this clause are building a fire escape they will almost certainly never be allowed to use, while sellers are negotiating carve-outs to a standard that already overwhelmingly favors them. The MAC clause defines what constitutes a sufficiently severe change in the target company's business, financial condition, or prospects between signing and closing that permits the buyer to refuse to close. Key variables include the definition of "materiality," the list of exclusions (carve-outs), the burden of proof, the temporal dimension (how long must the adverse effect persist?), and interaction with bring-down conditions on representations and warranties.
What Is a Material Adverse Change (MAC/MAE) Clause?
A Material Adverse Change clause, also called a Material Adverse Effect (MAE) clause - is a contractual provision in acquisition agreements that allocates the risk of significant negative developments occurring between the signing of the deal and its closing. The clause typically appears in two places: as a defined term (usually in Article I or the definitions section) and as a closing condition (requiring that no MAC has occurred as a condition to the buyer's obligation to close).
The MAC definition establishes the threshold of adverse change that must be met. It generally encompasses any event, circumstance, change, effect, or development that, individually or in the aggregate, has had or would reasonably be expected to have a material adverse effect on the business, assets, financial condition, or results of operations of the target company and its subsidiaries, taken as a whole.
Following the definition, the clause lists a series of carve-outs, categories of adverse changes that do not count toward a MAC determination. These carve-outs are the real battleground. Common exclusions include changes in general economic or market conditions, changes affecting the target's industry broadly, changes in applicable law or accounting standards, the announcement or pendency of the transaction itself, natural disasters, pandemics, and acts of war or terrorism. Many carve-outs include a "disproportionate impact" exception, which restores the change to MAC eligibility if the target is affected disproportionately relative to its industry peers.
The practical effect is that a buyer invoking a MAC must prove that the adverse development is specific to the target (not industry-wide or macroeconomic), is durational rather than temporary, and is sufficiently severe to substantially threaten the overall earnings potential of the target in a commercially reasonable manner. This is an extraordinarily high bar.
Why It Matters
Key Elements of a Well-Drafted Material Adverse Change Clause
Market Position & Benchmarks
Where Does Your Clause Fall?
Market Data
Sample Language by Position
Buyer-favorable: "Material Adverse Effect" means any event, change, effect, development, condition, or occurrence that, individually or in the aggregate, (a) has had or would reasonably be expected to have a material adverse effect on the business, assets, financial condition, results of operations, or prospects of the Company and its Subsidiaries, taken as a whole, or (b) would prevent or materially delay the ability of the Company to consummate the transactions contemplated hereby; provided, however, that none of the following shall be deemed to constitute, or shall be taken into account in determining whether there has been, a Material Adverse Effect: [limited carve-outs without disproportionate impact exceptions].
Market standard: "Material Adverse Effect" means any event, change, effect, development, condition, or occurrence that, individually or in the aggregate, has had or would reasonably be expected to have a material adverse effect on the business, financial condition, or results of operations of the Company and its Subsidiaries, taken as a whole; provided, however, that none of the following (or the results thereof) shall be deemed to constitute, or shall be taken into account in determining whether there has been, a Material Adverse Effect: (i) changes in general economic or political conditions; (ii) changes affecting the industries in which the Company operates generally; (iii) changes in applicable Law or GAAP; (iv) changes in financial or securities markets generally; (v) any epidemic, pandemic, or public health emergency; (vi) the announcement or pendency of this Agreement; except, in the case of clauses (i) through (v), to the extent such changes have a disproportionate adverse effect on the Company relative to other participants in the industries in which the Company operates.
Seller-favorable: "Material Adverse Effect" means any event, change, or effect that has had a material adverse effect on the business, financial condition, or results of operations of the Company and its Subsidiaries, taken as a whole; provided, that in no event shall any of the following, alone or in combination, be deemed to constitute, or be taken into account in determining whether there has been or will be, a Material Adverse Effect: [expansive carve-outs including (i) through (x), with no disproportionate impact exception on any carve-out, plus specific exclusion of effects arising from any matter disclosed in the Company Disclosure Schedules].
Example Clause Language
Public company merger agreement: Section 7.02(a). The obligations of Parent and Merger Sub to consummate the Merger shall be subject to the satisfaction or waiver of the following conditions: ... (ii) since the date of this Agreement, there shall not have occurred any Material Adverse Effect that is continuing as of the Closing Date. For the avoidance of doubt, the determination of whether a Material Adverse Effect has occurred shall be made by reference to the Company and its Subsidiaries, taken as a whole, and shall be measured from the date of this Agreement.
Private acquisition (with quantitative guidance): For illustrative purposes (but without limiting the generality of the foregoing), a decline in the Company's trailing twelve-month revenue of twenty percent (20%) or more, measured against the twelve-month period immediately preceding the date of this Agreement, and persisting for at least two (2) consecutive fiscal quarters, shall be deemed to constitute a Material Adverse Effect, provided that such decline is not primarily attributable to any event described in the carve-outs set forth above.
Leveraged buyout agreement: Notwithstanding anything to the contrary herein, the Buyer's obligation to consummate the transactions contemplated hereby shall not be conditioned on the availability of financing. For the avoidance of doubt, the occurrence of a Material Adverse Effect shall excuse the Buyer's obligation to close, but the Buyer shall not be entitled to assert the unavailability of debt financing as a failure of any closing condition, including the condition set forth in Section 7.02(a)(ii).
Common Contract Types
Negotiation Playbook
Key Drafting Notes
Common Pitfalls
Jurisdiction Notes
United States: Delaware law dominates MAC jurisprudence. The landmark Akorn v. Fresenius (Del. Ch. 2018, aff'd Del. 2018) established the modern framework: a MAC requires an adverse change that is "consequential to the company's long-term earnings power over a commercially reasonable period, measured in years rather than months." The court found a MAC for the first time in Delaware history based on a 50%+ decline in the target's core business metrics, regulatory violations, and falsified data. Prior decisions (IBP v. Tyson Foods, Hexion v. Huntsman) had rejected MAC claims. Post-COVID, no Delaware court has squarely addressed whether pandemic-related declines constitute a MAC where the pandemic carve-out is ambiguous. Practitioners should note that New York law, which governs many credit agreements, may apply a different (and potentially less demanding) MAC standard.
United Kingdom: English law M&A transactions use MAC clauses less frequently than US deals, partly because the UK Takeover Code limits the ability to invoke conditions (including MAC conditions) in public takeover offers unless the Panel on Takeovers and Mergers consents. For private acquisitions, MAC clauses are drafted similarly to US practice but are interpreted under English contract law principles, which may be more literal and less purposive than Delaware's approach. The concept of "material" under English law has not been as extensively litigated in the M&A context, creating interpretive uncertainty.
European Union and other jurisdictions: Continental European M&A practice varies significantly. German law transactions may use MAC conditions but are subject to the general principle of good faith (Treu und Glauben) under the BGB, which may constrain a buyer's ability to invoke a MAC opportunistically. French law similarly imposes good faith obligations. In cross-border transactions, the choice of governing law for the MAC clause is critical, as the substantive standard and judicial willingness to enforce MAC terminations differ materially across jurisdictions. In Asia-Pacific deals, MAC clauses are increasingly common but case law is sparse, and parties should expect that local courts may apply unfamiliar interpretive frameworks.
Related Clauses
This glossary entry is provided for informational and educational purposes only. It does not constitute legal advice, and no attorney-client relationship is formed by reading this content. The legal standards governing Material Adverse Change clauses vary by jurisdiction and are subject to evolving case law. Consult qualified legal counsel before drafting, negotiating, or invoking a MAC clause in any transaction.
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