This paper analyzes the financial statements of 58,653 firm-years from 34 countries between 1985 and 1998 to construct a panel dataset measuring three dimensions of reported accounting earnings: earnings aggressiveness, loss avoidance, and earnings smoothing. These dimensions are hypothesized to be associated with uninformative or opaque earnings. The study combines these three measures to create an overall earnings opacity time-series measure per country. The paper explores whether these measures affect two characteristics of an equity market: the return shareholders demand and the level of trading in the stock market. The results show that an increase in overall earnings opacity is linked to an economically significant increase in the cost of equity and a significant decrease in trading in the stock market. However, the relationship between individual earnings opacity measures and the cost of equity and trading is inconsistent. The study also finds that earnings opacity is significantly associated with variables that may impact the overall quality of a financial reporting regime, such as the CIFAR disclosure index and the number of auditors per 100,000 population. The paper concludes that earnings opacity affects equity markets by increasing the cost of equity and decreasing trading, but the relationship between individual earnings opacity measures and these market characteristics is not consistent. The study is part of a growing body of international accounting literature examining the value-relevance of accounting measures and the effects of earnings informativeness on equity markets. The paper also discusses the limitations of the earnings opacity measures and the challenges in measuring earnings opacity across countries. The study uses a panel data approach to test the effects of earnings opacity on equity markets and finds that earnings opacity is associated with higher cost of equity and lower trading in the stock market. The paper also discusses the implications and limitations of the study, including the potential for measurement error and the difficulty in capturing all factors that may influence earnings opacity.This paper analyzes the financial statements of 58,653 firm-years from 34 countries between 1985 and 1998 to construct a panel dataset measuring three dimensions of reported accounting earnings: earnings aggressiveness, loss avoidance, and earnings smoothing. These dimensions are hypothesized to be associated with uninformative or opaque earnings. The study combines these three measures to create an overall earnings opacity time-series measure per country. The paper explores whether these measures affect two characteristics of an equity market: the return shareholders demand and the level of trading in the stock market. The results show that an increase in overall earnings opacity is linked to an economically significant increase in the cost of equity and a significant decrease in trading in the stock market. However, the relationship between individual earnings opacity measures and the cost of equity and trading is inconsistent. The study also finds that earnings opacity is significantly associated with variables that may impact the overall quality of a financial reporting regime, such as the CIFAR disclosure index and the number of auditors per 100,000 population. The paper concludes that earnings opacity affects equity markets by increasing the cost of equity and decreasing trading, but the relationship between individual earnings opacity measures and these market characteristics is not consistent. The study is part of a growing body of international accounting literature examining the value-relevance of accounting measures and the effects of earnings informativeness on equity markets. The paper also discusses the limitations of the earnings opacity measures and the challenges in measuring earnings opacity across countries. The study uses a panel data approach to test the effects of earnings opacity on equity markets and finds that earnings opacity is associated with higher cost of equity and lower trading in the stock market. The paper also discusses the implications and limitations of the study, including the potential for measurement error and the difficulty in capturing all factors that may influence earnings opacity.