If contract terms supplied by one party are unclear, an interpretation against that party is preferred.
A party may be responsible for the formulation of a particular contract term, either because that party has drafted it or otherwise supplied it, for example, by using standard terms prepared by others. Such a party should bear the risk of possible lack of clarity of the formulation chosen. It is for this reason that this Article states that if contract terms supplied by one party are unclear, there is a preference for their interpretation against that party. The extent to which this rule applies will depend on the circumstances of the case; the less the contract term in question was the subject of further negotiations between the parties, the greater the justification for interpreting it against the party who included it in the contract.
A contract between A, a contractor, and B for the construction of an industrial plant contains a provision drafted by A and not discussed further stating that “[t]he Contractor shall be liable for and shall indemnify the Purchaser for all losses, expenses and claims in respect of any loss of or damage to physical property (other than the works), death or personal injury caused by negligence of the Contractor, its employees and agents”. One of A’s employees plays around with some of B’s equipment after working hours and damages it. A denies liability, contending that the provision in question covers only cases where A’s employees act within the scope of their employment. In the absence of any indication to the contrary, the provision will be interpreted in the manner which is less favourable to A, i.e. as also covering cases where its employees are not acting within the scope of their employment.