This is a proprietary volume metric that aims to assess the recent volume trend. It compares the average daily volume over the last 10 trading days with the average daily volume over the last 3 months expressed as a percentage.
This is calculated as (last 10 trading day volume divided by the average daily volume over the last 3 months) minus 1 * 100, i.e. the ratio will be negative to the extent that the average daily volume over the last 3 months exceeds the last 10 days' trading volume.
Tape Readers have long insisted that Technical Analysis is ultimately the analysis of price and volume movements. Increasing volumes can show institutional demand for a stock is increasing and should be watched carefully. The big institutional funds cannot trade in and out of a stock without leaving their footprints, and learning to read the signs in daily and weekly volume is important. If current volumes are higher than previous volumes while price is increasing, it may be a sign of fund accumulation hence the indicator flashes green.