The speculator can be considered as the counterpart of the hedger. He offers insurance opportunities, i.e. the possibility to cover positions against risk.
He believes that he is capable of anticipating future price fluctuations. Furthermore, he takes action in order to diversify the risks and thus is able to accept various risks, which, taken individually, would seem unreasonably high.
A special case would be a market maker, who has to manage the risk associated with extremely large positions.