Abstract

This contribution examines whether the share price of the Borussia Dortmund GmbH & Co. KgaA (BVB) behaves according to the (capital) market efficiency hypothesis of Fama (1970). The weak form of capital market inefficiency, according to which past share prices cannot be used for predictions in order to achieve above-average returns, is not refuted. By contrast, the hypothesis of medium-level market efficiency, according to which all publicly available and relevant information is immediately reflected in the share prices, is rejected. Based on daily quotation of share prices, the stock market price of the BVB shares adjusts to a deviation from the long-term equilibrium by (only) 5.4 % on the first day. Based on weekly calculations, the adjustrnent stands at 17 % in the first week. The investment motives of the shareholders and the relatively low volume of trade can hardly explain the medium-level capital market inefficiency. Missing learning effects of participating actors due to the short time of notice of BVB shares could be a more fruitful explanation.