That’s very helpful, thanks GAT. I know you have been fairly consistent in your message to avoid the front end of GE, so this just further adds to the list of reasons. I am currently working on my generic stitching algo and hopefully once I have mastered the vagaries and liquidities of the different delivery schedules (a lot less straightforward than I envisaged - some don’t even have consistent calendars), hopefully I should be able to pull up such useful vol comparisons as well. On a related subject, I have read your stuff on data storage and I was wondering if you still keep your price data on csv files, I find them easiest to munge data manually when the code isn’t sufficient, or have you migrated the live system to something faster like HDF or even sqlite? For a slow system would it even matter? If your database choices are proprietary these days, I would of course completely understand.