With the deepening of economic integration, it is important to study the spillover effect of macroeconomic uncertainty among regions along with social network knowledge. Based on microblog users' network connection, this paper analyzes the network factors that affect the uncertain spillover...

We study effects of correlation ambiguity on portfolio choice when the number of risky assets is large. We find that the optimal portfolio contains only a fraction of available risky assets. With 100 stocks randomly selected from the S&P 500, less than 20 stocks will be held in the optimal...