Quote from wareco:
Hello? Why do you think I posted the links? Its 30%. Geez.
Oh, sorry, I didn't click on it. My bad.
Anyway, it is NOT 30%. At least you can not say as a rule. There are 7 scenarios, depending on the speed of the fall.
In Scenario #6 if the Dow fall 20% after 2 pm it closes for the day, thus the max. for that day is 20% and not 30%.
In scenario #1 if the Dow fall only 10% by 2 pm, there would be 1 hour halt and if they really reopen (what I would seriously doubt) in the last 1 hour it is anybody's guess how much it could fall. But not more than another 10% because there would be another halt and we have ran out of trading time.
My guess is that those halts were implemented to give time to try to found out, just what is the cause of the selling. In the case of a terror attack, there is no way they would reopen after a 1-2 hours halt. They would probably stay close for a few days just like after 9/11....
So as a summary, it is safe to say that they would halt trading after a 10% fall, except if it is rather evenly distributed and happens only after 2:30...
As a last point, the worst case scenario #7 is practically useless, because to fall 30% the market has to fall first 10% and 20% and there would be 2 1-1 hour halts, and there is no way that let's say around 3 pm after 2 halts they would reopen to see if it can fall another 10% in the last hour....