What's Behind Wild Final Hour of Trading

NEW YORK (CNNMoney) -- If the daily 200-point drops or spikes in the Dow aren't enough to cause heart palpations among investors, the seemingly inexplicable gyrations in the final hour of trading probably do. "There have been more pronounced moves in that last hour that are more violent than in the other five and a half hours of the day," said Peter Boockvar, equity strategist at Miller Tabak + Co.