A Structural Matrix Autoregressive Model for the Joint Dynamics of Volume, Volatility, and Returns
How price swings drive trading volume across stocks in real time
Researchers built a statistical model that tracks how stock returns, price swings, and trading volume move together across all 30 Dow Jones companies. They found that volatility—how much prices bounce around—is the main force pushing people to trade, and that shocks ripple between stocks to drive more than half of long-term volume swings.
Understanding what actually drives trading volume helps market regulators spot abnormal activity and traders design better strategies for executing large orders without moving prices. The finding that volatility leads volume rather than the reverse overturns an old assumption and suggests that markets are primarily incorporating news through price discovery rather than through volume surges.