Volume flow: are buyers or sellers in control?

Classic volume only tells you ‘how much was traded’. Volume flow goes one step further: it separates how much of that trading happened at moments when buyers dominated and how much when sellers dominated. The difference between the two is called ‘delta’. If delta is positive, buying pressure has outweighed selling recently; if it is negative, selling pressure has.

In the chart above you see a grey line over price: this is an average weighted by delta; it gives more weight to prices where buying pressure was heavy. The line in the lower panel is volume relative to its average. If there is a coloured, sloping line over price, it is a delta divergence: price is making a new high (or low) while buying (or selling) power is not moving the same way. A red line means ‘price is rising but buyers are fading’, a green line ‘price is falling but sellers are fading’.

This resembles an RSI divergence, but it measures money rather than speed. If the force carrying price up is weakening, the fuel behind the advance may be running low. The evidence card also writes, as a percentage, whether buyers or sellers have dominated recently.

One thing not to forget: volume flow is only as strong as the volume data itself. For some BIST data sources volume can arrive as zero for licensing reasons; in that case volume flow is not calculated and the system does not draw it.

The most useful way to use volume flow is to combine it with a level. If selling pressure fades as price falls into an important support, sellers may be getting tired at that level. If buying pressure strengthens as price pushes against resistance, there may be real demand behind the breakout.