can be used to show accumulation or distribution for a stock. A rising OBV could indicate a reversal for a weak stock or confirm an upward trend for a rising stock. Likewise a falling OBV could indicate a reversal for a strong stock or confirm a downward trend for a falling stock.
For each day,
if Close > Close-1 OBV = OBV-1 + Volume,
otherwise if Close < Close-1 OBV = OBV-1 - Volume.