MACD, which stands for Moving Average Convergence / Divergence, is a technical analysis indicator created by Gerald Appel in the 1960s. It shows the difference between a fast and slow exponential moving average (EMA) of closing prices.

Most analysts say that the MACD indicator is "the difference between 12-day and 26-day exponential moving averages." However, the indicator is really the difference between 0.15 and 0.075 exponential moving averages (whereas, when expressed in decimal form, the 12- and 26-day exponential moving averages are actually 0.153846 and 0.076923 exponential moving averages).

When the MACD falls below the signal line, it is a bearish signal, which indicates that it may be time to sell. Conversely, when the MACD rises above the signal line, the indicator gives a bullish signal, which suggests that the price of the financial instrument is likely to experience upward momentum.