From the article: "A single
mysterious computer program that placed orders — and then subsequently canceled
them — made up 4 percent of all quote traffic in the U.S. stock market last
week, according to the top tracker of high-frequency trading activity. The motive
of the algorithm is still unclear.
The program
placed orders in 25-millisecond bursts involving about 500 stocks, according to
Nanex, a market data firm. The algorithm never executed a single trade, and it
abruptly ended at about 10:30 a.m. ET Friday." Read more
