ONE year ago, the stock market took a brief and terrifying nose-dive. Almost a trillion dollars in wealth momentarily vanished. Shares in blue-chip companies were traded at absurdly low prices. High-frequency traders, who use computers to look for microscopic price differences in stocks on different exchanges and other trading venues, stopped trading, while others immediately sold whatever they bought, mainly to each other, in what has been called “hot potato” trading.
Preventing the Next Flash Crash