Aleatory contract

An aleatory contract is a contract where an uncertain event outside of the parties' control determines their rights and obligations. For example, gambling, wagering, or betting, typically use aleatory contracts. Additionally, another very common type of aleatory contract is an insurance policy.

The term was a classification that was developed in later medieval Roman law to cover all contracts whose fulfilment depended on chance, including gambling, insurance, speculative investment and life annuities. The French civil code contains a chapter on aleatory contracts, with specific provisions for gaming (gambling) and life annuities. Many modern forms of derivatives and options may in some cases also be considered aleatory contracts.