A 71-character posting on hacked Associated Press twitter account saying the White House has been attacked and President Barack Obama had been injured sent stocks plunging on Tuesday afternoon.
But, the markets just as quickly rebounded to where they were before the tweet, once it became clear both that both the White House and the president were safe. The tweet was a hoax from a hacked account.
Here is that posting from AP's twitter account, coming at 1:07 pm Eastern (10:37 pm Indian time): "Breaking: Two Explosions in the White House and Barack Obama is injured."
Wall Street was in complete panic. The Dow fell 143 points, from 14,697 to 14,554 - worth an estimated $200 billion -after the fake posting, and then quickly recovered.
The past few days had been bad - with the Boston bombings and explosions in a Texas fertilizer plant - and market just believed the tweet. Most people did.
However, the wire service quickly announced that its account had been hacked: "The @APTwitter account has been suspended after it was hacked. The tweet about an attack on the White House was false."
The White House reacted too, with press secretary Jay Carney saying at the daily briefing, "I can say the president is fine. I was just with him."
The Associated Press said in a report later that an outfit calling itself the 'Syrian Electronic Army' claimed responsibility for the hacking. This, the agency added, couldn't be corroborated.
Other media outlets whose Twitter accounts were hacked by this outfit are the BBC weather, Al Jazeera and CBS news network's 60 Minutes and 48 House.
The FBI and the Securities and Exchange Commission (SEC) are investigating the hacking and its impact on the market, first-ever Tweet-driven crash.