Efficiency of Stock Market

This study has tested the semi-strong form of efficient market hypothesis by examining the stock price responses to quarterly earnings announcements. The sample consists of 156 companies listed on Bombay Stock Exchange, India. The companies are divided into three portfolios, good news, bad news and overall portfolio on the basis of percentage changes in quarterly earnings and sales. We use raw and log returns, market model, event study methodology, t-test, runs test and sign test. This study presents results on stock price responses to quarterly earnings announcements and seasonal analysis. For all the three portfolios under market model with raw returns and market model with log returns stock price behaviour around quarterly earnings on an average produced abnormal returns in pre-and post-announcement periods. Further, the abnormal returns were found to persist up to 31 trading days after the quarterly earnings announcement. The results indicate that the stock price adjustment to the event is delayed and persists throughout the event window. Therefore, the results of this study show that Indian stock market is not efficient in semi-strong form.