What Is a Material Adverse Change (MAC)?
M&A deals sign before they close, sometimes many months apart, and the MAC clause, often drafted as a material adverse effect or MAE, allocates the risk of the business deteriorating during that window. It typically appears both as a representation stating that nothing materially adverse has occurred and as a closing condition that lets the buyer walk away if something does.
Definitions are heavily negotiated and dominated by carve-outs. Sellers exclude changes stemming from general economic conditions, industry-wide trends, market movements, and events like war or natural disasters, so a MAC generally requires something specific to the target itself. Many carve-outs snap back, however, if the target is disproportionately affected relative to its industry peers.
How MAC Clauses Work in Practice
Delaware courts, which govern most large deals, have set a high bar. Under the standard articulated in cases like IBP v. Tyson in 2001, a downturn must be durationally significant, measured in years rather than quarters, and consequential to the target's long-term earnings power. Short-term earnings misses, even sharp ones, rarely qualify as a MAC.
The first Delaware decision to actually let a buyer terminate on MAC grounds came in 2018, when the Court of Chancery found in Akorn v. Fresenius that Akorn's steep, sustained EBITDA decline combined with serious regulatory compliance failures constituted an MAE. The COVID-19 era then produced a wave of MAC disputes, most of which, including LVMH's attempt to abandon its Tiffany acquisition, ended in renegotiated prices rather than court-sanctioned terminations.
Why the MAC Clause Matters
The MAC clause is the main risk allocation lever for the signing-to-closing period, and its negotiation reflects bargaining power: buyers want broad definitions with few carve-outs, while sellers want the reverse. Because invoking a MAC almost always triggers litigation, its real-world function is often as leverage to renegotiate price, with nervous buyers cutting deals during downturns rather than fighting in court.
For interview purposes, understand that a MAC claim is rarely successful and know Akorn v. Fresenius as the exception that proves the rule. On live deals, junior bankers see MAC negotiations shape everything from the length of the outside date to whether a buyer will accept a heavily carved-out definition to stay competitive in an auction.
