Force Majeure in Swiss Contract Law

Definition

Swiss law has no general statutory definition. The Federal Supreme Court defines force majeure as an extraordinary, unforeseeable and irresistible event that cannot be prevented by reasonable measures. Classic examples: natural disasters, wars, terrorism, pandemics. Fortuitous events are related but distinct: unforeseeable but not necessarily irresistible.

Subsequent Impossibility (art. 119 CO)

Art. 119 para. 1 CO: when performance becomes impossible due to circumstances not attributable to the debtor, the obligation is extinguished. Must be objective (impossible for anyone) and definitive. The debtor is released; in bilateral contracts, they lose the right to counter-performance and must return what was received (art. 119 para. 2 CO).

Conditions

Objective impossibility: not merely more difficult or costly. Not attributable: if the debtor is responsible, art. 97 CO (damages) applies instead. Subsequent: arising after contract conclusion. Pre-existing impossibility may render the contract void (art. 20 CO).

Contract Adaptation (clausula rebus sic stantibus)

When performance remains possible but becomes excessively onerous due to fundamental change of circumstances, courts may exceptionally adapt or dissolve the contract. Strict conditions: unforeseeable, fundamental change; no other contractual remedy. Applied with great restraint.

Contractual Force Majeure Clauses

Parties may define force majeure events and consequences contractually, providing legal certainty beyond art. 119 CO.