Research Paper (postgraduate) from the year 2019 in the subject Business economics - Economic Policy, Carl von Ossietzky University of Oldenburg (Wirtschafts- und Rechtswissenschaften), language: English, abstract: This paper examines the influence of the ESG-Score on the market value. Unlike most researches, this one does not only concentrate on the effect of a single ESG-Score. Instead, it is a natural experience, analysing the impact of an exogenous event on a firm's market value. More precisely, the influence of a law's implementation to disclose sustainable belongings of a firm. The two countries that introduced aforementioned law were Denmark in 2009 and France in 2012. By using a Difference-in-Differences Approach, significant changes in market value for firm's obligated to report within those countries are analysed and compared to other firms non obligated, listed in the STOXX Europe 600. The estimates suggest a significant negative influence on the market value for firms obligated to report situated in the post-intervention. Further, the negative influence increases with a complementary increase in delta ESG-Score. Those results suggest that a company should not suddenly abdomen itself to sustainability from one year to another. It is advisable to gradually address the matter in order to not negatively influence the market value of the company. Sustainable thinking is a movement of modern world society that can be noticed each passing day. When comparing the year of 2009 with the one of 2012, an increase in socially reasonable investment assets of 22 percent is noticeable. Besides, an ever-increasing number of people are joining environmental protest groups and pressure governments over the world to act. They want the government to, for example, force firms to produce more sustainable. Therefore, Corporate Social Responsibility (CSR) is becoming increasingly important in the daily business of a company. Many firms consequently responded by publishing a sustainability report each year and with that voluntarily report about environmental and social concerns of the company. Often, they disclosure such a report to legitimize their behaviour and actions. The government of Denmark reacted in 2009 and the one of France in 2012 to named protests with a law requiring companies meeting certain criteria to publish a report that contains non-financial information.