You sure? I think it's more like "I don't care if the index touches my short - as long as it expires just above it" and theta is very much the name of the game here as the theta burn is so high for 0 DTE options. Which is their attraction. Here's a screen shot taken seconds ago of the 3900-3890 Put credit spread on the SPX expiring today, with the IV's (highlighted in yellow). I cannot see the high IV skew you speak of. Sure, the longs IV is slightly higher (17.98) compared to the shorts (17.62), but where is the problem with this? I'm not trying to be awkward, or prove that you are wrong and that I am right - I am trying to understand what you mention in your posts.
it doesn't matter how you formulate it. You are betting against (short option) or on (long option) a strike touch. When you trade vol (or longer term options for that matter) you are betting on the fact that the market moves less (short option) or more (long option) than the options imply by trading the option and rebalancing the delta. Because you don't hedge delta with these short term coin flips at all, you set up the trade and hope that your short strike is not challenged -> bet against strike touch. if IV is "slightly" higher or much higher can be checked by looking at the vega of the option. When these 0.38 vols represent a tick, that's what you're paying over the short options fair value. I'm not saying what these guys are doing is wrong. When there is edge, there is edge, but I highly doubt it. You receive 55cts for a 9.45$ risk here which doesn't necessarily have negative expected value, BUT this combo is insanely execution sensitive, as it really matters over the long term whether you get 60cts credit or 50cts. On top of that you would not want to evaluate these options with a standard BS model because: 1.) These things don't trade until settlement. Settlement for SPX options can be either AM settlement or PM settlement. With AM settlement, the settlement value is determined by the opening price of the underlying components the next business day after expiration. So if you trade today, the option is not settled until tomorrow. If you now feed 1day (or 0.0039 years) into your BS model, you're actually getting the wrong number because you're missing the time between the close and the settlement 2. As mentioned, BS uses time in years and retail software calculates volatility (and greeks) by using todays return vs. yesterdays close which you compare by trading intraday on a daily chart.
why are you obsessed with strike 'touch' when that is only a major factor at the end of day feel free to tell us
Just read the posts, everything is already layed out. Elaborating further would be casting pearls before swine in your case
I said, back to your sandbox...you have a couple of years of simulator ahead of you to understand what we're talking about here