This study examines how stock market returns and volatility responses to macroeconomic news announcements in US and Europe, and oil prices. Moreover, the market risk associated with these stock markets based on selected countries and regions is also analyzed here. In all chapters, the data is in a weekly time horizon and it covers 21 countries from different contents. In particular, Data covers three different time periods, i.e. full sample from 1/1/2000 to 12/31/2015, before the financial crisis, i.e. from 1/1/2000 to 9/27/2008 and after the financial crisis, i.e. from 10/11/2008 to 12/31/2015. Chapter 2 studies the impact of macroeconomic news announcements on stock markets in 21 countries using US and European countries macroeconomic news announcements. The first part investigates the impact of macroeconomic news announcements surprises in US and European Countries on stock markets returns in these countries. The second part analyzes the impact of macroeconomic news announcements in US and European Countries on stock markets volatility in these countries. Our results show that stock markets in selected countries react differently to macroeconomic news announcement in US and Europe. Chapter 3 study the interaction and volatility spillover between oil prices and stock markets returns and volatility in selected countries and regions. Oil prices are based on West Texas Intermediate (WTI). The analysis use VAR(1)-GARCH(1,1) model to capture the interdependence between stocks market and oil prices. The findings show that there is interdependence between stock markets and oil price changes in most selected countries and regions. Chapter 4 study the market risk in stock markets returns in selected countries and regions using IGARCH(1,1) and GARCH(1,1) to obtain the value at risk (VaR) and the expected shortfall (ES). The findings of chapter 4 show that market risk was high for most selected countries before the financial crisis and low after the financial crisis.