1.   Computer-guided trading contributed to the swings.

2.   Excessive trading also contributes to wide swings in specific shares and the overall market.

3.   The consequences are large, since studies show that investors who trade frequently get lower returns and heavy trading contributes to wide swings in the market.

4.   The consequences are large, since studies show that investors who trade frequently get lower returns, and heavy trading contributes to wide swings in the market.

5.   Computerized trading contributed to the afternoon trend, added Jeffrey Sarrett, another Credit Lyonnais Securities trader.