Anti-stacking clause

Definition

Imagine: your SPA carries a de-minimis of €3k per claim and a €30k basket cumulative. The buyer discovers post-closing that one supplier contract was interpreted unusually, with financial impact spread across 14 different invoices averaging €2,500 each: €35k total. Can the buyer file these as 14 separate claims, or must they treat them as one?

Without anti-stacking: 14 separate claims, each below the €3k de-minimis, all blocked. With aggressive buyer interpretation: 14 claims grouped by context, total €35k above the basket, full €35k claimable (or €5k under deductible structure). The difference between no claim and a €5-35k claim depends on whether the SPA speaks explicitly to claim aggregation.

Benelux market norm in well-drafted SPAs in 2026: an anti-stacking clause explicitly stating that all claims arising from the same "underlying factual circumstance" or "single source of breach" are treated as one claim for the de-minimis test, but can aggregate as separate claims for the basket test (provided each individually exceeds de-minimis). That distinction: anti-stacking for de-minimis, not for basket: is the most seller-favourable standard position.

Buyers often resist anti-stacking because it gives sellers meaningful protection. But in mid-market deals where sellers carry adequate leverage, this is a well-negotiable point. We see sellers who draft this clause carefully experience on average 15-25% fewer cumulative R&W payouts versus sellers who accept the standard buyer template.

Worked example

A Brussels software firm was sold for €8m. The SPA carried a tipping basket of €25k and de-minimis €2k per claim. 11 months post-closing the buyer filed 9 claims for "incorrect commercial contracts treatment", each between €1,800 and €3,200, totalling €22k. The seller pointed to the anti-stacking clause explicitly stating that claims from the same "underlying factual circumstance" are treated as one claim for de-minimis. The Brussels commercial court ruled: the 9 claims arose from the same commercial-contracts interpretation and were one claim of €22k. One claim of €22k = below the €25k basket = no payment. Without anti-stacking: 9 individual claims above the €2k de-minimis = €22k that would have tipped the full €22k under the tipping basket. Difference: €22k of seller protection.

When it matters

In every SPA carrying R&W clauses with de-minimis and basket structure. Negotiate it explicitly: buyer templates rarely contain it by default, and silence in the SPA is typically interpreted by courts in the buyer's favour (each individual fact treated as standalone unless otherwise specified). Three negotiation points: (1) anti-stacking for de-minimis specifically, (2) definition of "underlying factual circumstance": narrow or broad, (3) anti-stacking should not block basket aggregation (an over-aggressive seller position that buyers almost always reject).

Frequently asked

Is anti-stacking standard in Benelux SPAs?

Not by default: buyer templates rarely contain it. But in well-negotiated mid-market SPAs (where the seller has leverage or an M&A advisor reviews the SPA) anti-stacking for de-minimis is included in ~60% of deals. Buyers initially resist but typically concede.

What is a "single source of breach"?

A factual circumstance giving rise to multiple financial consequences. Examples: one mistaken commercial-contract interpretation cascading across 15 invoices; one undiscovered tax liability spanning multiple tax years; one missed compliance requirement triggering multiple fines. The SPA must explicitly define how broadly this is read.

Can anti-stacking block the basket test as well?

Sellers sometimes want this; buyers almost always reject it. Market norm: anti-stacking for the de-minimis test (claims from one source stay below the threshold), but individual claims can aggregate for the basket test. This balance protects sellers from triviality while letting buyers claim genuine cumulative damage.