A trading game allows players to engage in trading based on real-world prices of real-world securities. Simulated positions of real-world securities in player portfolios may be opened and closed in accordance with instructions provided by each player. The performance of each player may be tracked relative to an index. A tradescreen may be generated for displaying current financial information of a portfolio of a player and for entering hypothetical data to produce revised financial information. The hypothetical data may be submitted to update the portfolio of the player.