套利（英语：Arbitrage，又称套戥），通常指在某种实物资产或金融资产（在同一市场或不同市场）拥有两个价格的情况下，以较低的价格买进，较高的价格卖出，从而获取低风险的收益。

套利，通常指在某种实物资产或金融资产（在同一市场或不同市场）拥有两个价格的情况下，以较低的价格买进，较高的价格卖出，从而获取丰厚的收益。例如，某支股票同时在伦敦和纽约交易所上市，同股同权，但是在纽约标价10美元，在伦敦却标价12美元，投资者就可以在纽约买进，到伦敦卖出。又比如在货币交易上进行套利，如借入利息较低的货币为融资，买进高息货币以赚取汇差或利差，例如，日圆放款利息长年维持在近乎零的水平，而南非或巴西等国因其通胀严重，利息常年维持在高水平。如果借入日圆来购买南非币或巴西里拉，在不考虑汇差情况下，也能赚取丰厚的利差。

Covered interest arbitrage is an arbitrage trading strategy whereby an investor capitalizes on the interest rate differential between two countries by using a forward contract to cover (eliminate exposure to) exchange rate risk. Using forward contracts enables arbitrageurs such as individual investors or banks to make use of the forward premium (or discount) to earn a riskless profit from discrepancies between two countries' interest rates. The opportunity to earn riskless profits arises from the reality that the interest rate parity condition does not constantly hold. When spot and forward exchange rate markets are not in a state of equilibrium, investors will no longer be indifferent among the available interest rates in two countries and will invest in whichever currency offers a higher rate of return. Economists have discovered various factors which affect the occurrence of deviations from covered interest rate parity and the fleeting nature of covered interest arbitrage opportunities, such as differing characteristics of assets, varying frequencies of time series data, and the transaction costs associated with arbitrage trading strategies.