Triangular Arbitrage is a situation that arises when exchange rates do not exactly match up - Exchange Rate Discrepancies . Say you had k1 units of currency A. When converted to currency B, k1 becomes k2. When converted to currency C, k2 becomes k3. Ordinarily , when we convert k3 to currency A, we get k1 back. But, in this condition, we would get more than k1 ! As cool as this sounds, for an average person, it is hopelessly impractical because these are few and far between. Furthermore, Low profits require large trades done very quickly - a job for automation software .