OBV (On-Balance Volume)

OBV (On-Balance Volume) is a cumulative volume indicator described by Joseph Granville in 1963: on up candles the volume is added to a running total, on down candles it is subtracted. Only the line's direction matters, not its absolute value — a rising line confirms a trend, while a divergence between price and OBV warns of a fading move. On forex MetaTrader computes OBV from tick volume (the number of quote changes), so it is only an approximation of real turnover.