On Balance Volume (OBV) is a technical indicator used in market analysis to measure the volume flow accumulated or distributed in an asset. OBV combines price and trading volume to forecast upcoming price changes.

On Balance Volume (OBV) was developed by Joe Granville in 1963 as a way to predict stock price movements based on trading volume.

The basic principle of OBV is that volume changes often precede price changes. OBV is calculated by adding the trading volume on days where the closing price rises, and subtracting the trading volume on days where the closing price falls.