How PoT works: An internet search on "Probability of Touching" + ThinkOrSwim will find at least three PDFs in ToS's library. Tom Preston is the creator.Quote from sle:
Ok, now that we mentioned schooling, let me make a couple points.
First, lets clarify the actual trading style. You are not really selling volatility per se, you are trading the terminal distribution. My understanding is that your selection is based on the following criteria
(a) proportion of the price of the spread to the width of the spread
(b) probability of touching the higher stirke based on some measure (you have not explained how it works just yet)
If you are using the implied volatility for the POT calculations, then you are creating a degenerate system - ratio of premium to the width of the spread is the indicator of probability of touching. If you are using probability of touching based on some other parameters (e.g. historical volatility, historical distributions etc), it would be a valid approach to capture alpha, albeit a very risky one.
Degenerate system?: Since PoT is proprietary, I cannot state with certainty what its inputs are. However, for your degenerate hypothesis to be true, the premium/spread ratio should be nearly constant. It does not.
Risky: Well covered here and elsewhere.
