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.
Legal references
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.
Frequently asked questions
Common questions about this term.