Delta measures net aggressive buying versus selling — volume traded at the ask (buyers lifting offers) minus volume at the bid (sellers hitting bids). It's a read on who's in control beneath the price. When price and delta diverge at an extreme, the move is weaker than it looks.

What the divergence looks like

Bearish delta divergence: price makes a new session high, but delta makes a lower high — the new high came on less aggressive buying, so the rally is running on fumes. Bullish: price makes a new low but delta makes a higher low — the selling is drying up. It's the RSI-divergence idea applied to raw order flow instead of a smoothed oscillator, which makes it more immediate.

How to use it

Use delta divergence as an exhaustion filter at levels. When price pushes into a wall or a range extreme and delta diverges, that's confirmation the move into the level is exhausting — a higher-quality fade. Combined with absorption (heavy volume that doesn't move price), it's a strong reversal read at an extreme.

Price can make a new high on shrinking buying — that's a rally living on borrowed time. Delta shows the fuel gauge the price doesn't.

The honest limits

Delta data requires order-flow tools and is noisy — divergences can persist before price turns, so it's confirmation, not a trigger. It's most reliable at a level (not in mid-air) and in a reversion-friendly regime; in a strong trend, delta can diverge repeatedly while price keeps going. Use it to grade a level-based fade, not to pick tops and bottoms on its own.