Insider trading in its legal form, called corporate insider trading or Directors Dealings, is around the financial market, since stock markets have existed. Some countries established earlier than others regulations, to prevent abuse and fraud. While the Anglo-American area was leading on this field for a long time, the European mainland caught up and invented a statistically significant regulation system. While the focus for corporate insider trading was long in the USA, recent studies also focused on the influence of such transactions on the European stock market. Through six hypotheses, the informational gap between insiders and the market is analyzed and tested, by using cumulative abnormal returns and the market model following literature. The data provided is from the German stock market and focusses on the industry sector. The results are presented in four time spans, as well as for sales and purchases separately. In general significance is found during most time periods for all hypothesis. The null hypothesis gets mostly rejected by the first test statistic, while less significance is found for the second. The formulated hypotheses are partly confirmed as in the literature. Further research, with a bigger sample and similar allegations, can prove evidence for results, where no significance is found.