When the “Flash Crash” wiped some $1 trillion of companies’ market value on May 6, 2010, when the US Dow Jones Industrial Average dropped 700 points before rebounding in a matter of minutes, the sudden plunge in stock prices was partially due to computers setup with “High-Frequency Trading Strategies“, in which thousands of orders to buy and sell shares are executed in fractions of a second.

The Nikkei 225 stock index closed down 10.55 percent on Tuesday March 15, 2011, recovering from deeper losses earlier in the session, as the nation grappled with a crisis at an earthquake-damaged nuclear power plant and the aftermath of last week’s earthquake and tsunami.