Competitive analysis of gold trading and its risk-reward model

Gold trading is a typical online decision problem in our real life. Considering the actual situation, the investors may have some forecast for the trend of gold price. In order to receive better income they would rather take some risks. Considering the situation that gold price will exceed m in the future, we present the risk-reward model and give the new online pricing strategy. Then the competitive ratio is obtained. Finally, the numerical analysis shows the improvement of competitive ratio in the new prediction and the impact on constraint competitive ratio γ_A´ by the risk tolerance d and forecast m.