Corporative Game Theoretic Application in Stock Selection Optimization

Although Markowitz initially could present a compounded model of risk-return trade-off, the model was incapable of dealing with real constraints. One of financial market characteristics is conflict of interest among market players which cause to the main trend of market be derived by market player’s interactions and each player’s strategy be a function of the other’s play. The second one is uncertainty. Both features are analyzed in Game Theory in order to optimize decision making process. In this paper, united players with negative, less than one, more than one and zero beta, established a coalition against the Market and tried to select securities that enable them to outperform it. The Market used its mean plus and mines three standard deviation as its strategies. Then player’s payoff in each strategy is determined based on how its return is better than Market and Risk free return and also how its Sharp ratio is better than the Market one. After running the game and finding the Shapely value, the optimized weights of each player and each security was calculated. The findings shows that united players won seventy five percent of twelve annual periods ending March 2018 regarding Treynor and Sharp Ratios. Also their performance was meaningfully better than the Market in the whole twelve year period.