I dug in to their 606 data for March.   For the month:  SP500 $2.7mm (366mm shrs) @ .0074/share non-SP500 $14.7mm (6.4bn shrs) @ .0023/share Options $28.1mm (54.4mm contracts) @ .52/contract  Avg SP500 $136.04/shr..   $100's of Billions to Trillions in notional/qtr.