Impossibility of performance

Impossibility of performance means that the agreed performance cannot be carried out. In Swiss obligations law, initial impossibility may affect whether a valid obligation arises, while subsequent impossibility concerns a duty that was possible when assumed but later becomes impossible. Consequences depend on whether the debtor is responsible, whether the impossibility is objective or merely personal, and whether a substitute performance or damages are available. If no party is at fault and performance is truly impossible, the obligation may be extinguished, with restitution issues for benefits already exchanged.