I have received following e mail from IB. I cant clearly understand and why are they doing this. Comments much appreciated
Change in Margin for Short Out-of-the-Money Equity Index Future Options
Please note that, at 12:00 ET today, in addition to the exchange-mandated margin calculations, IB will begin to gradually implement options margin based upon +/- 30% moves in equity index futures products. In addition to the current SPAN range of 16 scenarios, IB will consider 2 additional scenarios of +/- 30% moves in the underlying and will begin to margin affected positions accordingly. This implies that there will be an increase in the margin on short out-of-the-money equity index future option positions. It has been determined that, based upon the positions in your account at yesterday's close and the market conditions and applicable parameters at that time, your account will be affected by this increase in margin. Please manage your risk accordingly.
Also, please note that, going forward, IB will be gradually increasing the margin required on short out-of-the-money options that fall within the +/- 30% scan range.
Interactive Brokers Customer Service
Change in Margin for Short Out-of-the-Money Equity Index Future Options
Please note that, at 12:00 ET today, in addition to the exchange-mandated margin calculations, IB will begin to gradually implement options margin based upon +/- 30% moves in equity index futures products. In addition to the current SPAN range of 16 scenarios, IB will consider 2 additional scenarios of +/- 30% moves in the underlying and will begin to margin affected positions accordingly. This implies that there will be an increase in the margin on short out-of-the-money equity index future option positions. It has been determined that, based upon the positions in your account at yesterday's close and the market conditions and applicable parameters at that time, your account will be affected by this increase in margin. Please manage your risk accordingly.
Also, please note that, going forward, IB will be gradually increasing the margin required on short out-of-the-money options that fall within the +/- 30% scan range.
Interactive Brokers Customer Service