What Does OBV Mean and How Does On-Balance Volume Indicate Trend?
OBV is a simple volume indicator with a clear job. It tracks whether volume is flowing into or out of an asset, so you can check whether a price trend has real support behind it.
What Does OBV Mean: Definition
So, what does OBV mean? OBV stands for on balance volume. It's a running total that adds volume on up days and subtracts it on down days.
Joseph Granville introduced the OBV indicator in a 1963 book on stock market timing. His idea was that volume often moves before price. When buyers keep stepping in, OBV rises, even if price hasn't broken out yet. If you'd like a refresher on plain volume bars first, this overview of the volume indicator explains how to read them.
The OBV Formula
The on balance volume formula compares each close with the one before it:
Close higher than the day before: OBV = previous OBV + today's volume
Close lower than the day before: OBV = previous OBV - today's volume
Close unchanged: OBV = previous OBV
Only the direction of the close matters. A tiny gain counts the whole day's volume as positive. That keeps the math simple, but it can also overstate quiet days. A single heavy session, such as an earnings day, can shift the line sharply, so look past one-off spikes before you read too much into a move.
A Worked Example
Here's OBV over five days, with the running total starting at zero on day 1.
Day | Close | Volume | Change | OBV |
|---|---|---|---|---|
1 | $10.00 | 20,000 | Start | 0 |
2 | $10.20 | 25,000 | +25,000 | 25,000 |
3 | $10.10 | 15,000 | -15,000 | 10,000 |
4 | $10.10 | 18,000 | 0 | 10,000 |
5 | $10.40 | 30,000 | +30,000 | 40,000 |
Price rose $0.40 over the period, and OBV climbed to 40,000. Volume was heavier on up days than on down days, which supports the move.
Using OBV to Confirm a Trend
The simplest use is confirmation. In a healthy uptrend, price makes higher highs and OBV does too. In a downtrend, both make lower lows. When they move in step, the trend has volume behind it.
If price rises but OBV stays flat, be careful. The move may lack broad participation, and many traders treat that as a reason to tighten stops or wait. Comparing price with an indicator this way is a common idea, and this guide to bullish and bearish divergence with RSI applies the same logic to a momentum oscillator.
Bullish and Bearish Divergence Signals
Divergence happens when OBV and price disagree. In a bullish divergence, price makes a lower low but OBV makes a higher low. Selling pressure may be fading, and a move up could follow.
In a bearish divergence, price makes a higher high but OBV makes a lower high. Buyers may be losing interest, and the uptrend could stall.
Divergence is a warning, not a timing signal. It can last for weeks before price turns. Many traders pair it with a trend-strength tool, and this guide to ADX strategies shows one way to check whether a trend is gaining or losing force.
Why the Absolute OBV Value Doesn't Matter
The actual OBV number tells you very little. It depends on where the calculation starts. A chart whose data begins in 2015 and one that begins in 2020 will show very different OBV values for the same day.
What matters is direction and slope. Is OBV rising, falling or flat? Is it confirming price or diverging from it? Compare the line with its own recent highs and lows, not with a fixed number.
Check whether trends have real support.
Get StartedConclusion
OBV turns daily volume into a single running line. When it moves with price, the trend looks well supported. When it diverges, it's a cue to look closer. Treat it as one input among several, and set your risk before you act on any signal.
Disclaimer: Trading involves significant risk of capital loss and may not be suitable for all investors. Past performance does not guarantee future results.
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