The practice of profiting from differences between the way transactions are treated for tax purposes. The complexity of tax codes often allows for many incentives which drive individuals to restructure their transactions in the most advantageous way in order to pay the least amount of tax. Some forms of tax arbitrage are legal while others are illegal.

Tax arbitrage can, for example, involve recognizing revenues in a low tax region while recognizing expenses in a high tax region. Such a practice would minimize the tax bill by maximizing deductions while minimizing taxes paid on earnings. It is suspected that tax arbitrage is extremely widespread, but by its nature, it is difficult to give precise figures as to what extent tax arbitrage is employed.