The Coppock curve is a long-term price momentum indicator used primarily to recognize major bottoms in the stock market. It is considered to be an excellent tool for discriminating between bear market rallies and true bottoms in the stock market. The indicator was designed for use on a monthly time scale and is calculated as a 10-month weighted moving average of the sum of the 14-month rate of change and the 11-month rate of change for the index. A buy signal is generated when the indicator falls below zero and turns upward from a trough. Because the Coppock curve is a trend-following indicator, it does not pick an exact market bottom, but may identify rallies and reveal when a new bull market has begun.