The act of trading in an asset, or conducting a financial transaction, that has a significant risk of losing most or all of the initial outlay, in expectation of a substantial gain. With speculation, the risk of loss is more than offset by the possibility of a huge gain; otherwise, there would be very little motivation to speculate. While it is often confused with gambling, the key difference is that speculation is generally tantamount to taking a calculated risk and is not dependent on pure chance, whereas gambling depends on totally random outcomes or chance.
Speculators play one of four primary roles in financial markets, along with hedgers who engage in transactions to offset some other pre-existing risk, arbitrageurs who seek to profit from situations where fungible instruments trade at different prices in different market segments, and investors who seek profit through long-term ownership of an instrument's underlying attributes. The role of speculators is to absorb excess risk that other participants do not want, and to provide liquidity in the marketplace by buying or selling when no participants from the other categories are available. Successful speculation entails collecting an adequate level of monetary compensation in return for providing immediate liquidity and assuming additional risk so that, over time, the inevitable losses are offset by larger profits.