That's the thing. There are numerous trade confirmations and layers of authorization on orders that large. That's why I and a lot of other people are saying this may have been organic, set off by a liquidity halt in the EU.
Here's the IB release:
Quote:
Latest IB Notice
To all traders:
Thu May 6 21:49:58 2010 EST
UPDATE TO TRADE CANCELLATION NOTICE
IB has received notice from the venues listed below of their intent to cancel all stock trades executed between 14:40:00 and 15:00:00 which were executed at a price greater or less that 60% away from the consolidated last print in that security at 14:40:00 or prior. Each has also provided notification that this decision cannot be appealed. While we continue to await confirmation from all venues as to which stocks are affected and the break points at which the cancellations will take place, it now appears likely that the information will not be delivered within the timeframe necessary to be posted to your account until the morning. It should also be noted that IB has received no notice from the U.S. option exchanges or futures exchanges as to whether or not they intend to take similar action.
Again, once all relevant information has been determined, IB will act to process any resultant position and cash changes to your account and will provide notification of this action via email and TWS bulletin. As such changes may adversely affect account equity and/or margin compliance, account holders are advised to monitor their accounts and manage their risk accordingly.
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