Volume spread analysis, or VSA, studies the relationship between three things on each bar: its range (the spread from high to low), its close, and its volume. The core question is whether effort matches result — whether the volume spent produced a matching move.
When a bar has high volume and a wide range in one direction, effort and result agree — the move is genuine. When a bar has high volume but a narrow range, a lot of effort produced little movement, which suggests the other side is quietly absorbing the pressure.
Effort versus result
- High volume + wide range = effort and result agree; move is genuine.
- High volume + narrow range = heavy effort, little result — possible absorption.
- Low volume + wide range = a move on thin participation — treat with caution.
- Low volume on a pullback = healthy lack of opposing interest.
A classic VSA warning is a climax bar: enormous volume with a wide range at the end of a long trend, often followed by a stall. It suggests the last participants have piled in and there is little fresh demand left to push price further.
VSA is interpretive, not mechanical. It works best read at key levels and in context with structure, and any single bar can mislead. Use it to raise or lower your confidence in a move, not as a standalone trigger.
VSA asks whether effort matches result — heavy volume that fails to move price is often the tell that the other side is absorbing it.