“You are correct that our system does not automatically generate the margin which reflects the risk on the positions – it does not recognise option strategies and offsets, and will treat long positions and short positions independently. It also has limitations in how it treats short positions (it will never change less than 50% of the outright or futures margin rate, so in effect even if the delta is much lower than this it will put a 50-delta floor on it). It is for this reason that the Credit department does indeed do a manual override, using the scenario-based approach which has previously been explained to you. This is manual, prone to some error as noted above and time consuming, but we do set out to calculate an appropriate deposit requirement for the risk on each account.”