Abnormal Share Performance Stratified by Operating Changes

This table compares median cumulative abnormal returns in the 12-month post-listing period of firms that undertook major operational changes and firms that did not. Cumulative abnormal returns are computed relative to the S&P 500 for firms that announced operating changes over the year following focus list appearance in the 1991-94 period. A two-sided Wilcoxon signed-rank test is used to measure whether there is a statistically significant difference in cumulative abnormal returns between firms that made changes and those that did not. Sample sizes are shown in parentheses. Measures of change are based on reports in the New York Times and the Wall Street Journal.