Stock Price Response to Earnings Announcements: Evidence From the Nigerian Stock Market

The author examines the stock market reaction to annual earnings information releases using data for a sample of firms on the Nigerian Stock Exchange. Using the event study method, the author found that the magnitude of the cumulative abnormal returns is dominated by significant reactions 20 days before the earnings release date, which suggests that a portion of the market reaction may be due to private acquisition and, possibly, abuse of information by insiders. The persistent downward drift of the cumulative abnormal returns, 20 days after the announcement, is inconsistent with the efficient markets hypothesis.