Other forms: speculators
A speculator is someone who takes a chance on losing a lot of money when there's a prospect of making even more money. A speculator might, for example, invest in a risky stock in the hopes she can sell it eventually at a profit.
In a way, everyone who invests in the financial market is a bit of a speculator — the possibility of losing money is always there, as is a chance (and hope) of making money. Gamblers are speculators too, hoping to win big but vulnerable to losing everything on a poker game. Less commonly, a speculator is simply someone who speculates, or guesses without enough information. The financial meaning dates from the 18th century.