Earnings releases (ER) are normally accompanied by large stock-price movements, either to the upside or downside.
Here, we computed the percentage of companies that registered a large move in their stock price on their ER day in the trailing three-month window (500 basis points up OR down). In order to normalize for non ER-day volatility, we computed the percentage of all companies that registered a significant price move on any day during the same period. The difference between the two is shown in Chart 1.