%0 Journal Article %T Effect of Declaration of GST Rates and Changes in the GST Rates on the Sectorial Indices of National Stock Market %J - %D 2018 %X As per the Hypothesis of efficient market, the market is sectioned in three sections in view of how efficiently the market reacts to the private and public information. The main objective of this paper is to check whether there is a presence of volatility in the market due to declaration of GST rates and the declaration of changes in the GST rates and test semi-strong efficiency of Indian stock market. It was discovered that the declaration of GST rates and declaration of changes in GST rates did create an effect on the volatility of stock market. Goods and Service Tax has replaced the existing cascading taxes levied by the governments. It is going to change the way taxes are levied which effects the sentiments of the investors which can been analysed on the reaction of the investors towards stock market. The closing prices of NSE 10 sectorial indices and Nifty index has been used for conducting the study. The study is conducted using OLS, GARCH, and TGARCH. Thus, the study is useful to the regulatory bodies, investors and portfolio managers %K OLS %K GST %K GARCH %K TGARCH %K Efficient Market. %U http://scholarshub.net/index.php/ijcms/article/view/173