Bousoño Calzón, CarlosBustarviejo Muñoz, JosuéAceituno-Aceituno, PedroEscudero Garzas, José Joaquín2022-07-272022-07-272019-06-05Bousono-Calzon, C., Bustarviejo-Munoz, J., Aceituno-Aceituno, P., & Escudero-Garzas, J. J. (2019). On the Economic Significance of Stock Market Prediction and the No Free Lunch Theorem. In IEEE Access (Vol. 7, pp. 75177-75188). Institute of Electrical and Electronics Engineers (IEEE)2169-3536https://hdl.handle.net/10016/35522Forecasting of stock market returns is a challenging research activity that is now expanding with the availability of new data sources, markets, financial instruments, and algorithms. At its core, the predictability of prices still raises important questions. Here, we discuss the economic significance of the prediction accuracy. To develop this question, we collect the daily series prices of almost half of the publicly traded companies around the world over a period of ten years and formulate some trading strategies based on their prediction. Proper visualization of these data together with the use of the No Free Lunch theoretical framework gives some unexpected results that show how the a priori less accurate algorithms and inefficient strategies can offer better results than the a priori best alternatives in some particular subsets of data that have a clear interpretation in terms of economic sectors and regions.12eng© 2019 IEEEAtribución-NoComercial-SinDerivadas 3.0 EspañaStock MarketEconomic SignificanceForecastingPrediction AlgorithmTrading StrategiesExtended Bayesian FrameworkNo Free Lunch TheoremSupport Vector MachinesBig DataVisualizationresearch articleTelecomunicacioneshttps://doi.org/10.1109/ACCESS.2019.2921092open access7517775188IEEE Access7AR/0000024212