What is arbitrage? Arbitrage is the simultaneous buying and selling of identical financial instruments taking advantage of price discrepancies between different brokers, exchanges, clearing firms, etc. and thus locking in a profit. On paper, arbitrage is a risk-less trading strategy. In the real world however, risks abound.
So why trade arbitrage? Well, if the risks can be managed, arbitrage can be extremely profitable if you can find the opportunities and take advantage of the opportunities before they disappear. After all, the arbitrage opportunity is present because one side is slow to react to market news, momentum, etc. When it corrects the opportunity is gone.
Why arbitrage forex options? Well, because the opportunity exists if you look far it. The forex market is a cash inter-bank / inter-dealer market. In simplest terms, this means the foreign currencies traded in the forex market are traded directly between banks, foreign currency dealers and forex investors wishing either to diversify, speculate or to hedge foreign currency risk. The forex market is not a "market" in the traditional sense due to the fact that there is no centralized location for forex trading activity and, therefore, trades placed in the forex market are considered over-the-counter (OTC). Forex trading between parties occurs through computer terminals, exchanges and over telephones at thousands of locations worldwide.
Therefore the forex market is not as efficient as the NYSE for example. Price discrepancies exist between trading platforms, clearing firms, banks, etc if only for a small period of time. Options pricing is also affected for the same reasons but since there are other components involved in pricing an option than just the price of underlying currency, they tend to exist for longer periods of time.
One of the most common causes of option pricing differences is the calculation of volatility. Volatility is generally the standard deviation measured over a period of time. Sounds simple enough right? Well, if compare the volatility measure across different forex option providers, you