Negative Volume Index
The Negative Volume Index was introduced by Norman Fosback in his 1976 book, Stock Market Logic. Along with the Positive Volume Index, this indicator seeks to indentify bull and bear markets. It is based on the idea that there are a greater number of informed traders in the market on low volume days, while on high volume days the market is dominated by a greater number of unsophisticated traders.
Chart courtesy of Prophet Financial Systems (www.prophet.net)