Noretreat, I don't know how long the stock was halted. I saw my account balance plunge by a huge amount, scanned through to see what did it, and then saw that CLSN was halted. I checked the news which said it had been halted because of trading "triggered by a negative blog post on Seeking Alpha." So I quickly found it, and then the stock started trading again. I would estimate ten minutes that I was aware of it, but it could have been halted longer. There are rules for how long a price-triggered halt is supposed to last. It does look like a really short halt on this chart