On Balance Volume, developed by Joe Granville in 1963, was one of the first indicators to systematically combine price and volume data. OBV runs a cumulative total of volume — adding it on up days and subtracting it on down days — to reveal whether smart money is quietly accumulating or distributing before price reflects the move.
Joe Granville's core insight in 1963 was revolutionary: volume is the driving force behind price, and by tracking the cumulative flow of volume, you can detect institutional activity before it becomes visible in price. The calculation is elegantly simple.
If the current close is higher than the previous close: OBV = Previous OBV + Current Volume. If the current close is lower than the previous close: OBV = Previous OBV – Current Volume. If close equals previous close: OBV = Previous OBV (unchanged).
The result is a running cumulative total. If a stock has strong up days with high volume and weak down days with low volume, OBV rises steadily — reflecting that buyers are more committed than sellers.
The absolute value of OBV is irrelevant and changes depending on the start date of the calculation. What matters entirely is the trend of OBV and its relationship to price. A rising OBV in a rising price environment confirms the trend. A rising OBV in a flat or falling price environment reveals hidden accumulation.
Price is making lower lows or moving sideways. OBV is making higher lows or rising. This reveals that smart money is accumulating — buying on down days with significant volume while price appears weak. This frequently precedes a sharp price breakout as the accumulated position eventually drives price higher.
Classic scenario: A stock consolidates in a tight range for weeks. Price looks uninspiring. But OBV is steadily rising. On close inspection, the up days (even if small) have higher volume than the down days. Institutions are quietly loading a position. When they are ready to move, price will explode out of the range.
Price is making higher highs or moving sideways. OBV is making lower highs or declining. Selling pressure is increasing beneath the surface. Smart money is distributing — selling on up days while retail buyers chase the move. This is one of the most reliable signals of an approaching top.
OBV divergence must persist for multiple bars to be meaningful. A single day of divergence is noise. A 2–4 week divergence with OBV consistently trending away from price is a significant signal that warrants serious attention and position adjustment.
One of OBV's most valuable applications is its tendency to break above its own resistance levels before price breaks above price resistance. If OBV breaks out of a 6-week consolidation range while price is still below resistance, it is a high-confidence signal that the price breakout is imminent. This gives traders advance warning to position before the breakout occurs.
In a healthy uptrend, OBV should be making new highs along with price. When OBV confirms new price highs, the trend has genuine volume support. When OBV fails to confirm a new price high — this is the warning. The trend is still in place but the internal health is deteriorating.
| Price Action | OBV Action | Interpretation | Bias |
|---|---|---|---|
| Rising | Rising | Confirmed uptrend | Bullish — hold longs |
| Rising | Flat or falling | Bearish divergence | Warning — reduce exposure |
| Falling | Falling | Confirmed downtrend | Bearish — hold shorts |
| Falling | Flat or rising | Bullish divergence | Watch for reversal |
| Flat/Range | Rising | Hidden accumulation | Prepare for bullish breakout |
| Flat/Range | Falling | Hidden distribution | Prepare for bearish breakdown |
The most reliable breakouts are those where OBV breaks out simultaneously with or just before price. When price breaks above resistance and OBV confirms with a new high of its own, the probability of follow-through is dramatically higher than a price breakout with flat or declining OBV.
Consolidation periods are where OBV is most revealing. Price goes sideways — apparently quiet. But OBV is telling you whether volume is flowing in (accumulation) or flowing out (distribution). A stock in a 3-month range with steadily rising OBV is coiling like a spring. A stock in a similar range with declining OBV is a distribution trap.
The slope of the OBV line matters as much as its direction. A steeply rising OBV in a short period reflects aggressive, urgent buying — possibly before a major announcement. A slowly rising OBV over many months reflects patient, methodical accumulation — typical of institutional position building. Both are bullish but with different timescales and urgency.