The wider the limits are set by exchanges, the greater the risk of loss from expanded price moves.
But just what makes the price move and how do the oil markets work?
Some of the biggest price moves were in downward in gold.
Yesterday's price move was one of the smallest for the issue in several weeks.
The price moves have taken place on a steady increase in trading volume.
Volume was very light, exaggerating the size of the price moves.
"Once the price moves, the rumors are built around that movement," he said.
So the buying to keep these inventories level may have exaggerated the price moves.
But trading was thin, so all price moves were exaggerated.
If there are no significant price moves, nothing changes.