T2103 - Zweig Breadth Thrust
Developed by Martin Zweig, this indicator is calculated by taking a 10-day moving average of the number of advancing issues divided by the number of advancing issues plus the number of declining issues. Since it is a percentage indicator, it cannot go below 0 or above 100. However, it is rare that it goes below 40 or above 60. This indicator can be useful as an overbought/oversold indicator.
Greg Morris (G. Morris Corporation, Dallas, TX ) claims that Martin Zweig says any time this indicator thrusts from below 41 to above 60 in under 10 days that the market will be significantly higher 18 months later. We find the indicator useful as an overbought/oversold indicator, also.