Market insiders use the volatility of first-hour executions to fade clean trends and empty pockets. Conversely, the indicator subtracts the daily volume when that stock closes down. The econo- mies of scale in trading along with payment for order f low to discount brokerage firms has made it possible for them to grow at a very fast pace. Knight alone accounts for 17 percent of Nasdaq0OTC market share in June 1998.