Abstract Introduction: The effect of Environmental, Social and Governance issues on stock prices is highly debated in literature. Different authors state that ESG has an influence on stock price and company value while others state that it has no or limited effect. Purpose: The purpose of this research is to explain the effect of ESG changes on stock prices and add information to the debate between both sides if there is, or if there is not an effect from ESG on stock prices. Research questions: 1. What is the effect of changes in Environmental concerns in stock prices? 2. What is the effect of changes in Social concerns in stock prices? 3.What is the effect of changes in Governance concerns in stock prices? Methodology: Event study method with a sample size of 484 companies from the S&P 500 which will be analyzed for the period of 2015-2017, which gave 1.420 different events. These companies got ratings for Environmental Pillar, Social Pillar, Governance Pillar, ESG Controversies, ESG Score and ESG Combined Score. For each event the abnormal stock returns were compared with the rating changes. The data is taken from EikonThomsonReuters. Conclusion: The results showed no correlation between Environmental, Social and Governance rating changes and abnormal returns. Also, the combined ratings did not show any correlations. Therefore, our study will support and contribute to the side of researcher Friedman (1970), Jacobs et al. (2010), Walley and Whitehead (1994), Drobetz et al. (2004) and other researchers which state there is no correlation between ESG and stock prices. Limitations: The study is based on ratings provided by EIKON, we assumed they are a clear and correct reflection of the actual ESG within companies. The second limitation is the anticipation effect, the response of the stock market is based on unawareness from investors. If the bases where the rating changes on is already known than there is no effect from investors because they already anticipated the decreased rating. There are also a few companies excluded from the research because of missing ratings. Also, these results are based on the S&P500 and therefore do not have to be true for other financial markets. Keywords: ESG, Stock Price, Environmental, Social, Governance, ESG-ratings, S&P 500, Event Study, EIKON