The law of one price is an economic concept that states that the price of an identical asset or commodity will have the same price globally, regardless of location, when certain factors are considered.

The law of one price takes into account a frictionless market, where there are no transaction costs, transportation costs, or legal restrictions, the currency exchange rates are the same, and that there is no price manipulation by buyers or sellers. The law of one price exists because differences between asset prices in different locations would eventually be eliminated due to the arbitrage opportunity.