A risky situation can have more than one possible outcome. The probabilities of the various possible outcomes are not known. By that definition, most real-life situations involve uncertainty. You usually don't know the probabilities of the different things that can happen in real life. Uncertainty, though, is hard to analyze, so instead we usually assume that we do know the probabilities of all of the outcomes.
Games of chance are the situations that come closest to having known probabilities for all outcomes.
The probability, as they calculated it, of making a profit was a near-certainty. Two economists won a Nobel Prize in 1997 for working out the theory of this. Then, in 1998, Russia defaulted on its bonds. Investors, including these economists, got a very expensive reminder that there is uncertainty in securities. But, as I said, uncertainty is hard to analyze, so let's look at risk.