Quote from def:
The brokerage IB does not trade the other side of your trade as it does not trade on a proprietary basis. IB's affiliate Timber Hill (just like any other market participant) may take the other side of an order if it can offer the best price to an order.
I'd like to add one additional comment... You mention "profitable orders". When a liquidating order is sent to an exchange, no one knows that it is a liquidating order and no one knows at that instant in time whether or not the order will be profitable to the opposing side.
Reply to Def (part 2):
In short, the liquidation was erratic, and it seems apparent Timber Hill was first in line.
There are difficulties which have to be explained. IF IB merely wanted to send a message to their customers to increase concern position size, you don't need example setting for that!
A) It would be sufficient for that to be one of the informative pop-ups which appear on the IB screen when you first log in.
B) Minimally, if the customer explicitly requests/ requested information be forwarded to him relevant to the safety of his assets, IB would forward it to him or send him the appropriate link, especially if it is obvious to upper management the customer is oblivious to the danger (as occurred here), and especially if corporate IB is aware of the request.
C) It would be sufficient to for IB to program the auto-liquidation software to improve the RATIO, rather than to liquidate randomly!!
D) And if the software cannot be programmed, it would be sufficient to call the customer (even for $$600), or for a live broker to liquidate the position
As it stands now, IB earned themselves $11K (minimum; plus extras due to a shift in underlying stock price.). If IB concludes they are taking responsibility, then fine. If not, I just don't have any other way of understanding why IB would allow automation to work against instead of for the customer.