RE: Help14 May 2025 11:52
On AIM a buy is generally a PI or institution buying from market makers (intermediaries), a sell is a PI or institution selling to market makers. Think of it like a pawn shop, if I take my gold ring into the shop I am selling to the pawnbroker, if someone else comes in later that day and buys the ring he is buying from the pawnbroker (and will be making a chunky margin). Pretty much all websites classify trades depending on their relationship to the reported mid price, as either buys (above the mid price) or sells (below the mid price), .
This is sometimes quite inaccurate, particularly on days with high SP volatility, where there are lots of delayed trades, or where the MM's reported bid and ask prices aren't representative of prices you can actually sell or buy for. Sometimes MM's will deliberately set the bid or ask at misleading levels to make it look like trades are sells rather than buys i.e. set an unrealistically high ask on Level 2, which makes the mid price higher and allows trades just below the mid price to be reported as sells rather than buys.
Delayed reported trades are often not categorised as buys or sells, or mischaracterised as buys or sells, you often have to look at contemporaneous trades to figure out what they actually are. As previously stated, I follow L2, do dummy trades and consider the real mid price at the time of trades (rather than the reported one) to determine whether trades are buys or sells, which is pretty accurate, but also labour intensive.