I actually always glance at the ATM straddle and try to make sure my strikes are well outside of that range at a minimum.
If I can translate riskarb's comment into our English (and risk arb feel free to correct me), is that the ATM straddle is being priced by the market maker on current IV estimates to cover the potential range of index moves from that point to expiration. If the index is at 1260 and the 1260 JAN straddle is at $40.00 then the MM are pricing based on an expected distribution of 1300 and 1220 of the prices to expiration. Since they want to price the straddle so that they are covered on buy or sales, you assume that their straddle pricing is a their good estimate of the market range they see as of that moment over the life of the straddle. This changes daily with volatility and index changes but gives you the range distribution.
If I can translate riskarb's comment into our English (and risk arb feel free to correct me), is that the ATM straddle is being priced by the market maker on current IV estimates to cover the potential range of index moves from that point to expiration. If the index is at 1260 and the 1260 JAN straddle is at $40.00 then the MM are pricing based on an expected distribution of 1300 and 1220 of the prices to expiration. Since they want to price the straddle so that they are covered on buy or sales, you assume that their straddle pricing is a their good estimate of the market range they see as of that moment over the life of the straddle. This changes daily with volatility and index changes but gives you the range distribution.
Quote from riskarb:
You guys/gals should always be mindful of the atm straddle premium when choosing your strikes. The atm straddle is a pure-representation of the implied distribution to expiration.
Anyway, get back to the business at hand, sorry for the interruption.