With the end of the Bretton Woods agreements and the largest volatility of the interests and of the exchange rates, financial derivatives have been created with the initial purpose of covering risks. However, the use of those mechanisms was not restricted to that purpose, becoming a privileged instrument of speculation, given the possibility of high capital gains. Thus, it is necessary to differentiate and to understand the concepts of hedge, arbitrage and speculation, in face of the existence of derivatives markets, in which the companies have leveraged their positions.