I have in my trade window: 5x Bull Put Combo for 5$ total. That would be 10 Puts (5 buy and 5 sell). So a total of 10 option contracts for 5$. As well as: 5x Bull Put Combo (x2) for 14$ total. That would be a total of 20 Puts (5 B&S, and 5 B&S). So a total of 20 option contracts for 14$ I'm not doing anything special: 1) I do limit pricing (never tried market price). 2) I allow IB to route my order (SMART destination). 3) I do tend to trade in liquid options If I am trading a higher volume (100+) I sometimes fiddle with the routing, but still have noticed anything crazy with the pricing. For your situation: 1) Were you trading something very illiquid? (such that each contract was traded separately with a lag between it). 2) Were you trying to route it through something other than SMART (this can increase/decrease execution time and/or pricing). I have used IB since forever, and the collection of the pricing is favourable (lower margin rates, better cash interest rates, super douper option assignment fees, low/free withdrawl fees, and I have not seen anyone with better fixed income pricing). If taken in totality, I think IB is the most cost effective retail one out there. But if you are ONLY interested in one type of transaction, there may be better alternatives.
At the IB it comes down to averages. The average commission per side might sound too much in the beginning, but it gradually drops down once you carry on trading?
Unlike other brokers that may calculate margin at the end of the trading day and provide three-day margin calls, IB's advanced real-time margining system evaluates account risk and margin requirements in real-time throughout the trading day to keep you informed intraday regarding margin requirements and allow you to react more quickly to the markets providing you with enhanced customer support, Hence I would recommend you to contact them for your related query..