The On Balance Open Interest for an n-day period is defined as the sum of all Open Interest for up days minus all Open Interest for down days. An up day is one where the price closed higher or the same as the previous day. The On Balance Open Interest study calculates the n-day Open Interest for each day and charts it as a line which can oscillate around the zero line.
Presentation
Above is a Daily Line Chart of a British Pound Future (BP1600). The bold green line in the lower window pane represents the On Balance Open Interest line.
