The Dow Jones Average plunged Tuesday afternoon, but recovered quickly after it was revealed that an Associated Press tweet about explosions at the White House was fake. The AP acknowledged that its Twitter account had been hacked.
DAVID GREENE, BYLINE: Hackers got into the Associated Press's Twitter account yesterday and sent out a fake tweet saying that the White House had been attacked. Though the tweet was discredited very quickly, it created a swift and panicked reaction on the stock market.</s>DAVID GREENE, BYLINE: Here's NPR's Jim Zarroli.</s>JIM ZARROLI, BYLINE: The tweet said that a pair of bombs had gone off in the White House and President Obama was injured. Almost instantaneously, the Dow Jones Industrial Average fell 125 points.</s>JIM ZARROLI, BYLINE: Joe Saluzzi of Themis Trading says the dizzying speed with which stocks fell was almost certainly because of widely used high-speed computer trading programs.</s>JOE SALUZZI: Nowadays, machines or computers can read news. So there's something called machine readable news which is sold to the highest bidder and there are many companies out there doing it, where they sell feeds and the machines read 'em and automatically trade off the news.</s>JIM ZARROLI, BYLINE: The incident was over almost as soon as it began. Stock prices rebounded and finished the day higher. But Saluzzi, a longtime critic of high speed trading, says the plunge underscores how vulnerable the markets are to this kind of computer program.</s>JOE SALUZZI: To us, it's just another symptom of a market which has been broken for years.</s>JIM ZARROLI, BYLINE: Saluzzi says yesterday's incident calls to mind the infamous "flash crash" of May 2010, when the Dow dropped by 9 percent in the space of a few minutes before rebounding. A report from federal regulators later said the crash had been aggravated by high-speed trading programs.</s>JIM ZARROLI, BYLINE: Jim Zarroli, NPR News, New York.