An individual can react to news when it breaks, rather than waiting for the opening bell when everyone else has the same information, as is the case in many markets. This may enable market participants to take positions before an important piece of information is fully factored into the exchange rate. High liquidity and 24 hour trading allow market participants to exit or open a new position regardless of the hour. Size or quantity flexibility can be especially useful to corporate treasurers who need to hedge a future cash flow or portfolio managers who need to hedge foreign equity exposure. Currencies are traded in pairs, for example US dollar vs. yen or US dollar vs. Swiss franc.
Every position involves the selling of one currency and the buying of another.
If one believes the Swiss franc will appreciate against the dollar, one can sell dollars and buy Swiss francs. Or if one holds the opposite belief, one can buy dollars for Swiss francs. The potential for profit exists as long as there is movement in the exchange rate or price. In currency futures, the contract size is predetermined. If important data is released overseas while the U.S. futures markets is closed, the next day's opening might sustain large gaps with potential for large losses if the direction of the move is against your position.