Volume indicators are technical tools to evaluate a security’s bull and bear power. Most look specifically at buying vs. selling pressure to determine which side is in control of price action ...

It's a metric derived by dividing a stock's volume on up days by its volume on down days during the past 50 days. A ratio greater than 1.0 shows more volume on the upside than on the downside.

From ninjatrader.com Joseph Granville developed and introduced the on-balance volume (OBV) indicator to the technical analysis community in his 1963 book “Granville’s New Key to Stock Market Profits.” ...