OBV Explained: Reading Trends with On-Balance Volume

Price can be misleading, while volume may reveal more. OBV accumulates volume into a single line to show buying and selling pressure behind a trend. This guide covers the concept, divergence, and its limitations.

What is OBV?

OBV, or On-Balance Volume, was introduced by Joseph Granville in 1963. It adds or subtracts volume according to price direction to create a cumulative value. The calculation is simple.

• If today's close is above yesterday's, add today's volume to OBV.
• If today's close is below yesterday's, subtract today's volume.
• If the closes are equal, OBV does not change.

OBV's absolute value is not meaningful because it depends on the starting point. Its direction and slope matter. Rising OBV indicates accumulated buying pressure in volume terms, while falling OBV indicates selling pressure. The underlying assumption is that “volume precedes price.” It is used to check whether volume supports price movement.

Confirming trends through price–OBV divergence

OBV's main use is divergence from price. If price moves in one direction but OBV fails to follow, the trend's driving force may be weak.

Practical uses

1. Trend confirmation: Confidence in a price rally increases when OBV also makes new highs. If the two diverge, defer entry or reduce allocation.
2. Assessing breakouts: A break above resistance accompanied by surging OBV is considered more likely to be genuine. Quiet OBV raises suspicion of a false breakout.
3. Combining indicators: Establishing trend direction with moving averages, then checking OBV, can provide more confidence than OBV alone.

Limitations and precautions

OBV is not a universal solution. Keep these limitations in mind.

• Simple close-based addition and subtraction: A 0.1% rise adds the whole period's volume, just as a 5% rise does. It does not account for the size of the price change.
• Frequent false divergences: Divergence does not mean a trend will immediately reverse. Trends often continue much longer.
• Weaker in ranges: Signals are less reliable in directionless range-bound markets.
• Crypto volume reliability: Some exchanges' volume data contain noise, potentially distorting OBV's inputs.

OBV is a supplementary confirmation indicator, not a standalone trading signal. No indicator guarantees profits, and markets can move against expectations at any time. Setting a stop level before entry and managing risk with an appropriate position size come before interpreting indicators.