With the high-frequency data of firm quotes in the transaction platform of foreign exchanges, arbitrage profit opportunities--in the forms of a negative bid-ask spread of a currency pair and triangular transactions involving three currency pairs--can be detected to emerge and disappear in the...

Using the "firm" quotes obtained from the tick-by-tick EBS (electronic broking system that is a major trading platform for foreign exchanges) data, it is found that risk-free arbitrage opportunities--free lunch--do occur in the foreign exchange markets, but it typically last only a few seconds....

Using tick-by-tick data of the dollar-yen and euro-dollar exchange rates recorded in the actual transaction platform, a "run" -- continuous increases or decreases in deal prices for the past several ticks -- does have some predictable information on the direction of the next price movement. Deal...