OBV is a volume indicator and is, therefore, only used on futures contracts. It was developed and popularized by Joseph Granville in 1963. It assigns the volume for each day a positive or negative value depending on whether the market prices close higher or lower for that day. A higher close from the previous day results in the volume figure for the current day being assigned a plus value, while a lower close from the previous day counts for negative volume. A running cumulative total is then maintained as the market continues to trade. It is the direction of the OBV line that is important and not the actual numbers.

Volume Accumulation is also a volume indicator which was devised by Marc Chaikin. Whereas the OBV line assigns all of the day's volume a positive or negative value, volume accumulation counts only a percentage of the volume as a plus or minus, depending on where the close is in relation to its average price for the day.  If prices close above the mid point of the day's range a percentage of that day's volume is give a positive value. If prices close below the mid point, a percentage of the day's value is assigned a negative value. The only time the entire day's volume is assigned a positive value is when the close is the same as the day's high. When the opposite occurs, all the day's volume is counted as negative.