High-Speed Trading Glitch Costs Investors Billions
The glitch that sent markets tumbling Thursday was years in the making, driven by the rise of computers that transformed stock trading more in the last 20 years than in the previous 200.
The old system of floor traders matching buyers and sellers has been replaced by machines that process trades automatically, speeding the flow of buy and sell orders but also sometimes facilitating the kind of unexplained volatility that roiled markets Thursday.
“We have a market that responds in milliseconds, but the humans monitoring respond in minutes, and unfortunately billions of dollars of damage can occur in the meantime,” said James Angel, a professor of finance at the McDonough School of Business at Georgetown University.
In recent years, what is known as high-frequency trading — rapid automated buying and selling — has taken off and now accounts for 50 to 75 percent of daily trading volume. At the same time, new electronic exchanges have taken over much of the volume that used to be handled by the New York Stock Exchange.
In fact, more than 60 percent of trading in stocks listed on the New York Stock Exchange takes place on separate computerized exchanges.
Many questions were left unanswered even hours after the end of the trading day. Who or what was the culprit? Why did markets spin out of control so rapidly? What needs to be done to prevent this from happening again?
So it’s true; to err is human, to really screw things up you need a computer.
Farther down in the article it says the plunge may have been caused by a cascade effect from computer programmed trades which are set to sell when the market (or certain stocks) fall X%. Once they start dumping the ball is rolling.
As if human crooks weren’t enough to contend with.