2025-03-262025-03-2628-02-201908-06-2019https://pyxida.aueb.gr/handle/123456789/8424It goes without saying that the ability to predict the direction of stock/index is of paramount importance for the viability of the companies and individual investors. An accurate prediction of the sign of a stock index is an effective hedging strategy that can mitigate the risk level of companies. In essence, setting the risk is a mean that can yield a more efficient allocation of the companies' capital. In this study, eight different classification techniques were employed for the determination of the direction of the S&P 500. Two different approaches were used as inputs, first for the acquired principal components generated from PCA and second for our existing dataset. This comparison showed that Principal Component Analysis (PCA) negatively affect our results, except the KNN algorithm. Our experimental results verified the superiority of Support Vector Machines (SVM) in predicting financial time series.57 p.CC BY: Attribution alone 4.0https://creativecommons.org/licenses/by/4.0/Principal Component Analysis (PCA)Ridge & Lasso regressionRandom forestsNested cross-validationTradingMachine learningPrediction of stock market index movementFinancial forecastingNeural networksSupport Vector Machines (SVM)Text