This is a question that's been on my mind for some time. I would appreciate it if you guys could give me some pointers. SPY was last traded at 129 on Friday. If I were to do a calendar spread, say, long SPY JUN 129 CALL and short SPY JULY 129 CALL, what should I do if my short contract gets exercised, SPECIFICALLY when I don't have enough equity to deliver the underlying? It seems that brokers such as IB allow you to make this kind of trade even if you don't have enough equity to deliver the underlying in case a contract is exercised. Thanks again for your tips.