An aleatory contract
is a contract
in which the performance of one or both parties is contingent upon the occurrence of a particular event. The most common type of aleatory contract are insurance
policies. Such insurance contracts may be a boon to one party but create a major loss for the other, as more in benefits may be paid out than actual premiums received, or vice versa.
Gambling contracts and many modern forms of derivatives and options may in some cases also be considered aleatory contracts. For example, the French civil code contains a chapter on aleatory contracts, with specific provisions for gaming (gambling) and life annuities.