# Material adverse change (MAC)

Source: https://contracko.com/glossary/material-adverse-change

# Material adverse change (MAC)

A significant negative event that lets a party walk away or renegotiate a deal.

## Definition

A material adverse change (MAC) clause lets a party refuse to close or terminate a transaction if a significant negative event affects the target's business, finances, or prospects between signing and completion. It is common in M&A and financing deals to allocate the risk of deteriorating circumstances. Dutch civil law has no specific MAC statute; comparable relief might otherwise be sought through unforeseen circumstances (onvoorziene omstandigheden) under article 6:258, which sets a high threshold.

## Example

> A buyer invokes the MAC clause to abandon an acquisition after the target loses its single largest customer just before closing.

## Why this is a business risk

A poorly defined MAC clause can become the most contested provision in a deal. Buyers invoke it to exit deals that have become less attractive; sellers fight it to hold buyers to their commitment. Courts have set a high bar for what qualifies, so a MAC clause that fails to define qualifying events with precision may be commercially useless when you need it most.

## How to manage it

- Define MAC specifically: list the metrics (revenue, EBITDA, customer count) whose deterioration by a stated percentage constitutes a MAC.
- Carve out general market downturns, industry-wide events, and changes in law: courts have consistently held these do not qualify as a MAC because both parties share the risk.
- Set a short exercise window: the party invoking MAC must do so promptly or be deemed to have waived the right.

### How Contracko helps

Contracko stores MAC clauses with their defined trigger events as searchable metadata. In a portfolio of acquisition or financing agreements, the AI review can surface MAC definitions and carve-outs so your deal team knows instantly what protection each contract provides.

## Legal references

- [BW 6:258 Dutch Civil Code: unforeseen circumstances Dutch law](https://wetten.overheid.nl/BWBR0005289)

Unless marked otherwise, references are to Dutch law (Burgerlijk Wetboek, the Dutch Civil Code); EU instruments such as the GDPR apply across the EU. This is general information, not legal advice. Other jurisdictions treat these concepts differently. Verify the current text and your situation with a qualified lawyer.

## Relevant for

[Financial Services](https://contracko.com/industries/financial-services)[Commercial Real Estate](https://contracko.com/industries/commercial-real-estate)[Manufacturing](https://contracko.com/industries/manufacturing)

## Related clauses

- [Termination for Cause Clause](https://contracko.com/clause-library/termination-for-cause)
- [Warranties Clause](https://contracko.com/clause-library/warranties)
- [Price Indexation Clause](https://contracko.com/clause-library/price-indexation)

## Related terms

- [Force majeure](https://contracko.com/glossary/force-majeure)
- [Termination](https://contracko.com/glossary/termination)
- [Representation](https://contracko.com/glossary/representation)
- [Warranty](https://contracko.com/glossary/warranty)

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## Frequently asked questions

Common questions about this term.

- **Q:** Is there a Dutch-law equivalent to a MAC clause?
  **A:** There is no specific statute. Parties rely on the contractual MAC definition, since the general doctrine of unforeseen circumstances (article 6:258 BW) has a deliberately high threshold.

- **Q:** Have courts ever upheld a MAC claim?
  **A:** Rarely in M&A. US and UK courts have set a very high bar; general economic downturns, customer losses, and even significant revenue declines are typically not MAC absent specific drafting. The main exception tends to be catastrophic, company-specific events.

- **Q:** What is the difference between a MAC clause and a material adverse effect (MAE)?
  **A:** The terms are often used interchangeably. MAC tends to refer to the clause that permits a party to walk away; MAE is the defined event or effect that triggers the MAC right. Some agreements use MAC and MAE distinctly for different purposes.

- **Q:** Can a MAC clause be used in contracts other than M&A deals?
  **A:** Yes. MAC clauses appear in financing agreements (allowing lenders to withdraw a facility), long-term supply contracts, and joint ventures. Their structure is similar but the qualifying events are tailored to the specific context.

- **Q:** What obligations must a party meet before invoking a MAC clause?
  **A:** This depends on drafting, but typically the invoking party must give prompt written notice specifying the MAC event, and may need to negotiate in good faith before exercising the right to terminate or not close.

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