Dear IB reps, as you might know, I had pointed out some interesting points for you in the past. Here is another nice one: As we know, you are calculating the overall (all expirations/all series) implied vola for each stock. How about making historical implied vola data available for useage via Charts/the API? Like providing Bid/Ask/Midpoint data, maybe this is not too hard to implement at some point. This would probably be a premier in the industry, I do not know of any broker or data vendor to have such data.