Pardon the question if you've explained this elsewhere, my search didn't turn anything up, but why focus on the equity-only p/c as more representative of sentiment? The only reasons I can think of are 1) volume is higher on the equity p/c side, and 2) if market makers and hedge funds buy blocks of index puts to hedge long positions, it skews the index p/c up. But they can also hedge their long positions in individual stocks by buying puts in those stocks, or they can sell calls to all these exuberant retail investors, so I'm not sure the second reason makes sense. I'm missing something. Any other reasons? TIA