Quote from atticus:
Selling the 1475P/1475C in a 3/1 ratio. The risk at the short strike under a flat vol scenario is ~4.00 based upon the mark on the ATM straddle. The risk at the short strike dissects to 4 ATM options, so we take the current ATM straddle premium (*4) as the benchmark to derive the risk of touching the 1475 strike.
There is impact to symmetry and convexity (concavity) as sticky delta. There is an assumption under a static vol-surface that the OTM vol will converge to ATM vol as spot approaches strike. Of course the strips (unweighted strike vols) will rise if we drop, so a static "evolution of vol surface" scenario is not likely. It's beyond this thread, so you should google sticky-delta.
Gains from symmetry
Gains from "stickiness"
Loses on strip-risk on mkt drop
Loses below strike on delta(gamma)
Upside risk contained by size (ratio). Skew increases on our position as mkt rallies, but the risk is materially offset by a drop in strips and that we're not geared (as stated) on the upside.
They are initially neutral to delta, but the gamma-risk is represented in the puts. You can ignore 25% of your gamma figure as all the leverage is in the puts (gamma and speed).
I had a thread devoted to pitchforks and I traded one in the ES for illustration: http://www.elitetrader.com/vb/showthread.php?s=&threadid=244704&highlight=pitchfork I use the PF figure to monetize skew rather than something I trade frequently, but I trade 2-3 per month, mostly with OPM.
Not mentioned in the PF journal, but I usually have a limit-sell order resting on index futures for gap-risk. Typically 10:1 (puts over short futures).
Quote from atticus:
Doobs asked about the Mar14 SPX 1475 pitchfork and I think it looks decent here at 77.40 mid. The ATM combo is 40.75 mid (*2 = 81.50). The risk to strike at flat-vol is <4.10 (81.50 - 77.40). Strike vol is 250bp over ATM.