1. A computer-implemented method for forecasting a future event, comprising: providing a user interface which identifies parameters of a prediction market, the parameters include a question regarding the future event and a set of different outcomes of the future event, each outcome is represented by a respective security in the prediction market, the parameters are defined by a sponsor of the prediction market, and the user interface concurrently displays the set of different outcomes of the future event; receiving an input from a user, via the user interface, of an estimated probability of occurrence of each of the different outcomes of the future event; concurrently displaying, via the user interface, and in response to the input from the user, the different outcomes of the future event, and the user's estimated probability of occurrence of each of the different outcomes of the future event; for each of the different outcomes of the future event, automatically determining: (a) a proposed bet, an amount of the proposed bet is based on the user's estimated probability of occurrence of the outcome of the future event, and (b) a win amount based on the proposed bet; concurrently displaying, via the user interface, for each of the different outcomes of the future event: the outcome of the future event, the proposed bet and the win amount; receiving a user command, via the user interface, for accepting at least one of the proposed bets; and in response to the command, executing at least one trade in the prediction market for shares of at least one respective security which represents the at least one of the proposed bets, a number of the shares is based on the amount of the at least one of the proposed bets.