Hi. I had a calendar spread using weekly SPY 132 Put(10 contracts). The short leg was obviously deep in the money and was going to be assigned at expiry. I did not have the margin to cover the 1000 shares that would have been assigned, but still had the long leg of the 132 puts. The reason I did not close the chort leg, was since it was deep in the money, the spread was too big. As I understand, there is no risk in this position. IB liquidated my short leg at $2.5 premium after market close on friday, costing me about $2500. I could definitely have done much better than this price and would have if I had known this was going to happen. In the past they have assigned shares, but they decided not to assign at the worst possible time. Are they allowed to do a look-ahead margin call? They denied any compensation for this gross overpayment. My question for you guys is there any point in pursuing this? I have read that you can go to arbitration but do I have a case and if so, how can I go about it doing this? This has also led me to consider lightspeed trading? What you guys think about this broker? Thanks in advance.