Every trade in the futures market has a buyer and a seller. But one of them is always the aggressor, the one who crossed the spread to get filled now. Delta measures that aggression.

Bar delta

For each bar, delta is volume at the ask minus volume at the bid. A bar with +800 delta saw 800 more contracts bought aggressively than sold aggressively.

Cumulative delta

Cumulative delta (CVD) adds bar delta together through the session. It shows whether aggressive buyers or sellers have been in control overall.

Divergences

The most useful signal is when price and CVD disagree:

• Price makes a new high but CVD does not. Buyers are pushing less hard. The move may be running out of steam.

• Price makes a new low but CVD makes a higher low. Sellers are weakening.

• Price goes nowhere while CVD rises sharply. Aggressive buying is being absorbed by passive sellers.

Things to keep in mind

Delta is not a buy or sell signal by itself. It is most useful at levels you already care about. Strong delta in the direction of the trend is confirmation. Strong delta that fails to move price is a warning.

In HOC Charts

The CVD and Delta indicators in HOC Charts use live tick data, and you can show them as candles, a line or a histogram under your chart.