The moving average convergence divergence (MACD) is a popular momentum indicator that is used in technical analysis. The MACD is calculated by comparing exponential moving averages in a security's price. The MACD line is charted alongside a nine-day moving average of the MACD line, called the signal line, and a histogram representing the difference between these two curves. Traders use the MACD histogram to anticipate changes in market momentum. MACD analysis can still generate false price predictions. Experienced traders use additional metrics and fundamental analysis to support their forecasts.
This example should demonstrate how observing the MACD histogram can help anticipate changes in trends in both short-term and long-term price momentum. It is important for traders to learn to recognize these trends and not bet against them. Fighting a trend is a sure way to get pummeled.