when they want to. When they don't, we get .50 swings on a few hundred shares. Tens of thousands of shares have traded in the last two hours within a .20 range. The narrow range should be the norm. The wide swings just screw the small investor.
I wonder how much of the daily volume is real. It might be that much of the volume is just two or more MMs "painting the tape", trading back and forth with one another, moving the price up and down to pull people in or shake them out.