During yesterdays fun and games in the market, over the course of approximately 4 minutes, the Dow dropped 200 points. They’re still not 100% sure exactly what happened, but so far it seems to come down to this - the volume overwhelmed some servers and things “broke out” a little before 3PM. The bottom half of the chart is volume - see that nice little spike there? At one point they were thinking someone made a mistake and put too many zeros at the end of an order, but it seems to just been a whole boatload of unexecuted trades just queued up and waiting.
It will be interesting to see what effect (if any) this has on the continued use of the hybrid trading systems that have been introduced in the past year or so.
ETA @ 4PM - Specialists on the floor of the NYSE have been told not to close their stocks just yet. Curiouser and curiouser…

February 28th, 2007 - 4:17 pm
I wonder how many thousands I lost.
http://business.guardian.co.uk/story/0,,2023523,00.html
February 28th, 2007 - 4:35 pm
Dow came back almost a half percent today - appears the losses will be relatively short lived at least.
March 1st, 2007 - 12:10 am
Reminds me of the book Debt of Honor.