For example, you might think the Euro (EUR) is going to increase in value against the Australian dollar (AUD) so you could place a trade to buy the EUR/AUD currency pair. If the Euro rises you would make a profit; if it drops you would incur a loss. Conversely, if you thought the Euro was going to decrease in value you could place a trade that would benefit from that price movement.
To trade $100,000 of currency, with a margin of 1%, an investor will only have to deposit $1,000 into her or his margin account. The leverage provided on a trade like this is 100:1. Leverage of this size is significantly larger than the 2:1 leverage commonly provided on equities and the 15:1 leverage provided in the futures market. Although 100:1 leverage may seem extremely risky, the risk is significantly less when you consider that currency prices usually change by less than 1% during intraday trading (trading within one day). If currencies fluctuated as much as equities, brokers would not be able to provide as much leverage.