For the benchmark CL and NG contracts, the most recent option open interest: NG 219,000 option contracts American style NG 5.1 million option contracts European style CL 2.9 million option contracts American style CL 136,000 option contracts European style First, is there a reasonably simple explanation for why the European style dominates in NG but it's just the opposite in CL? Second, using "Option Trader" at Interactive Brokers, I get the NG Euro style listing, with a LAST, DELTA and IV, but no CHANGE, BID or ASK. When I try to input a trade, it rejects because the system can't calculate a margin. Anyone trade the NG Euro style options at IB? Did you have to make a special request to do so? Thanks