Except they have no way of figuring that out until the actual liquidation happens. Perhaps declaring the interval would be good, along with the range during that interval, for example, over the past 30 days the lowest exchanges would be this cap while the highest would be that cap. Or maybe if there were a way to see the proportion hodled during that same interval. But the "volume" that they report, do we know how much of that volume is repeat volume (same stock traded over and over during the interval) versus unique volume? I doubt it, right? A hard problem. The simple market cap based on the latest trade price is still a nice way to compare stocks.
Discussion
it's basically bullshit
i forget which kind of decay function tends to play in but i think it's a log10
so 10% sold price is 50% something like that
the actual orderbooks can tell you where it will go, momentarily, but if it goes down they won't tell you who has stop loss orders waiting to be triggered at whatever level, only the ones that have been registered, stops are supposed to be executed by trigger they are not telegraphed