RE: Filter22 Oct 2020 01:16
Here's a fuller explanation: https://www.proactiveinvestors.co.uk/companies/news/81/idiots-guide-to-the-london-stock-exchanges-setsmm-0379.html
The relevant para says:
"When an investor buys or sells stock from/to a market maker, the transaction is reported to the stock exchange. Each transaction is, of course, both buy and sell. You are the buyer or seller, and the market maker is the other party in the transaction. However, only one trade report is required. The transaction reports are published by the stock exchange with a trade type of O, and services such as ADVFN,iii and MoneyAM, who have a "feed" of information from the exchange, will list the transactions on their Monitor/Watchlist and Trades pages. Some years back, all the online services thought it would be a good idea to attempt to list these transactions as buys or sells, and devised a guesstimate system - if a transaction is executed at a price above the mid-price, it is placed into the buy column. If executed below the mid-price it is placed in the sell column.
Now, unless trading is intense and prices moving rapidly, these buy/sell columns are fairly accurate, and represent a reasonable estimate of the amount of buying/selling BY investors FROM/TO the market makers. "