RE: Lower Ask makes for a pretty blue screen28 Aug 2020 08:29
Technically true, but a market maker is the other side of the trade. If I sell, the mm is the buy side, and if I buy, the mm is the sell side. So what we'd like to know is whether it was a customer buy or a customer sell. The mms know this of course, but they're only required to report the trade itself, not whether it was a customer buy or sell. The midprice buy-sell division is an attempt to approximate the real buys and sells and it's common knowledge that in thinly traded shares the mms sometimes set artuficial bid and ask prices to create the illusion of customer buying or selling. But if you look at the bid and ask and the individual trades themselves, you can pretty accurately figure out which are buys and which are sells for about 80-90% of the trades.