An Asian option (or average value option) is a special type of option contract. For Asian options the payoff is determined by the average underlying price over some pre-set period of time. This is different from the case of the usual European option and American option, where the payoff of the option contract depends on the price of the underlying instrument at exercise; Asian options are thus one of the basic forms of exotic options.There are two types of Asian Fixed Strike option, the Asian Fixed Strike call and the Asian Fixed Strike put. In general they do not differ in definition, only in how the pay-off is calculated.