KEYWORDS:Efficient Market Hypothesis, Event Study, Semi Strong Form Of Efficiency, Stock Market Reaction, Indian Stock Market. INTRODUCTION: An empirical study to test the semi-strong form of efficient market hypothesis examines the
speed and accuracy of adjustment of stock prices to release of certain new relevant information.
Security prices are expected to respond to the relevant new information as and when it reaches
the market. In an efficient market, stock prices reflect available information fully and
instantaneously. In other words, efficiency of stock market is reflected in two ways, i.e. speed
and accuracy. Speed refers to time taken by the stock to respond to new publicly available
relevant information. Woodruff and Senchack (1988) asserted that the adjustment process is