Hi Gowtham
ORATS has historical relationships for all US equity options back to 2007 along with many other metrics.
We forecast short-term (30 day) and long-term (2 year) slope, which is roughly what you are describing.
You can set up an analysis to predict the relationship yourself.
Here is a chart of the 30 day IV 25 delta / 75 delta (we have 5, 25, 50, 75 and 95 deltas available):
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We describe this relationship as Slope and for ease of communication, turn it positive
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described here in the API docs: https://docs.orats.io/data-api-guide/core-research.html#implied-volatility-surface
Here's the Slope with the Slope Forecast and the ratio. When the ratio is high, we forecast slope to fall:
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Currently, the slope/forecast is near 1 meaning the slope is near our forecast.
How do you choose 75 delta and 25 delta? I think you pick the nearest strike. I have had problems with this.
For example, sometimes the closest delta to 25d could be 24.5d for several days. Then it could become 25.5d. That fact that historically we had picked 24.5d and today we are picking 25.5d itself with skew the ratio. How do we handle this?