An electronic stock trading system attempted to trade 100 Apple shares at almost 10% below their value late last week, but was caught out by a single-stock circuit breaker, a system which detects massive, unjustified changes in price.
Trading in Apple was briefly halted while the error was fixed, and shares in the company are now sitting comfortably over US$600.
The erroneous trade was caused by a glitch in the third-largest stock exchange system in the United States, called the Better Alternative Trading System, or BATS.
The fault affected companies with ticker symbols A through BF, which included BATS itself – in an unfortunate piece of timing, the company had launched an IPO that same day.
BATS stock fell from US$16 to just two cents due to the fault. It cancelled all trades in its stock and withdrew its IPO; on opening the company website a message is displayed for 15 seconds that says, "We know we can do better. And we will."
Go here to read the statement from BATS chairman, president and CEO, Joe Ratterman.