On-Balance Volume (OBV)

On-Balance Volume (OBV): The Smart Money Indicator

Updated: 2026-03-01 · Expert Analysis by Senior Trading Analyst · SEO Optimized for Beginners

Executive Summary

On-Balance Volume (OBV) is a momentum indicator that uses volume flow to predict changes in stock price. It is based on the theory that volume precedes price movement, acting as a "leading indicator" for institutional accumulation and distribution.

1. The Origin: Joseph Granville

OBV was developed by Joseph Granville in his 1963 book, "Granville's New Key to Stock Market Profits." Granville believed that volume was the "steam" that made the "locomotive" (price) move. He argued that when volume increases sharply without a significant change in price, the price will eventually "catch up" to the volume.

2. How OBV is Calculated

The calculation is surprisingly simple but incredibly effective:

If today's close is higher than yesterday's, today's volume is added to the previous OBV.
If today's close is lower than yesterday's, today's volume is subtracted from the previous OBV.
If the close is the same, the OBV remains unchanged.

3. Trading with OBV: Trend Confirmation

The absolute value of OBV doesn't matter; what matters is the trend of the OBV line. If the price is making higher highs and the OBV is also making higher highs, the trend is healthy and likely to continue. This is called "confirmation."

4. Spotting the "Smart Money" Divergence

This is the "Holy Grail" of OBV trading. If the price is flat or even dropping slightly, but the OBV line is rising sharply, it means institutional investors (the "Smart Money") are quietly accumulating shares. This "Bullish Divergence" often precedes a massive price breakout.

5. Conclusion

OBV is one of the most reliable indicators for understanding the "why" behind price movements. By tracking the flow of volume, you can see if a trend is supported by real conviction or if it's just a "fake-out" based on low-volume retail trading. Always look for OBV to lead the way.