We conduct a comprehensive study of commonality in liquidity using intraday spread and depth data from 47 stock exchanges. We find that firm-level changes in liquidity are significantly influenced by exchange-level changes across most of the world’s stock exchanges. Emerging Asian exchanges have exceptionally strong commonality, while those of Latin America exhibit little if any commonality. After documenting the pervasive role of commonality within individual exchanges, we examine commonality across exchanges. We find evidence of a distinct, global component in bid-ask spreads and depths. Local (exchange-level) sources of commonality represent roughly 39% of the firm’s total commonality in liquidity, while global sources contribute an additional 19%. We also investigate potential sources of exchange-level and global commonality. We show that commonality is driven by both domestic and U.S. macroeconomic announcements.

We examine the impact of block ownership on the firm’s trading activity and secondary-market liquidity. Our empirical results show that block ownership takes potential trading activity off the table relative to a diffuse ownership structure and impairs the firm’s market liquidity. These adverse liquidity effects disappear, however, once we control for trading activity. Our findings suggest that block ownership is detrimental to the firm’s market liquidity because of its adverse impact on trading activity—a real friction effect. After controlling for this real friction effect, we find little evidence that block ownership has a negative impact on informational friction. Our results suggest that the relative lack of trading, and not the threat of informed trading, explains the inverse relation between block ownership and market liquidity.