The main purpose of this study is to investigate the impact of implementation of goods and services tax on national stock exchange (NSE) of India by considering nifty 50 index of NSE India and by applying event study technique. India embarked upon a new era of global practices by embracing and implementing goods and services tax on 1st July 2017 which was considered as the “event” for this study. Nifty 50 index daily data from 12th June 2017 to 21st July 2017 (t ± 14 days) are used for the study. The result of the study suggests that implementation of GST impacted nifty 50 index of NSE in a positive way resulting in abnormal returns which is statistically significant. The results of the study provide fresh evidences on our understanding about impact of structural changes on stock market in short-run to regulators, potential investors and high net worth individuals, fund managers, hedge funds and policymakers.