Value investing as a strategy has a well-established history and has undergone extensive testing and studies within financial economics. Through the use of the strategy, studies and investors have demonstrated a positive return, where in many cases it has managed to generate excess returns compared to the market. The problem arises from the fact that the strategy should not be able to consistently generate excess returns compared to the market as it is not supported by the efficient market hypothesis (EMH). The purpose of the study is to investigate whether value investing as a strategy succeeds in generating excess returns on the Stockholm Stock Exchange. The method is based on a screening process, followed by a ranking system inspired by Joel Greenblatt’s value investment strategy "The Magic Formula". The method aims to systematically identify undervalued stocks based on the combination of two key ratios. Based on the applied method, two fictional portfolios were created with 15 stocks in each, based on value investing as a strategy. Historical data between 2013-2023 was collected to create the portfolios, with restructuring taking place each year based on set criteria. During this period, one of the portfolios showed a total return of 284.49%, which was an excess return compared to all benchmark indices in the study. The observed excess return suggests market inefficiency, where there may be opportunities for investors to identify and take advantage of undervalued stocks in the market. However, this excess return was not statistically significant when adjusted for risk, which in turn supports the EMH. Despite the strategy's success in generating excess returns compared to the market, it is therefore difficult to determine the level of efficiency at which the Swedish market has operated during the investigated period.