Volatility has increased because there is an increasing number of traders who have instant access to information and hence instantly react to news. The sheer mass of trades has the potential to abruptly move the stock price in one direction or another. Upwards momentum can therefore quickly build up and turn into exuberance, while downwards momentum could feed the starting of a panic selling movement.

 It is critical to compare the evolution of both price and volume changes on very small time intervals

• to assert if a sudden price change has been caused by an unusual volume change
• To quickly judge if the stock is entering extreme movements caused by exuberance or panic