3) I agree OI is going to be the goto but I'd caution to have a good feel for the underlying and market participants. It is not just market makers that sell calls - covered writes are a popular strategy by investors to pick up income. Vertical spreads are used by some punters too.
Puts are where it is likely to be just market makers on the short side - lots of insurance buying but few nakeds or covered shorts.
Regarding calls, do you have suggestions on how to figure out if the OI in some particular call is mostly market makers' short or investors' short?
I know you referenced "good feel for the underlying and market participants" in order to answer that question, but
I'm wondering if there's a specific idea you could suggest regarding that to help narrow my focus?
> It is not just market makers that sell calls
Would you guess that market makers are, on average, net flat, net short, or net long calls?
Puts are where it is likely to be just market makers on the short side - lots of insurance buying but few nakeds or covered shorts.