On Balance Volume (OBV) is a technical indicator that measures buying and selling pressure by cumulatively adding volume on days when the closing price rises and subtracting volume on days when it falls. Displayed at the bottom of the chart, the OBV line moves upward when today's closing price exceeds the previous day's and moves downward when it is lower. This indicator is used to identify potential breakouts ahead of price movements and to confirm upward trends. Traders using OBV may open positions at breakout price levels and set stop losses above recent high swings. The indicator is applicable in forex markets and supports breakout trading strategies.