Developed by Gerald Appel, the Moving Average Convergence/Divergence(MACD) is a momentum indicator used to show the relationship between a 26-day and 12-day Exponential Moving Average with a 9-day Exponential Moving Average (the "signal" or "trigger") line plotted on top to show buy/sell opportunities.

Three popular ways to use the MACD are:

• Crossovers: The basic MACD trading rule is sell when the MACD falls below its signal line and buy when the MACD rises above it. It is also common to buy/sell when the MACD goes above/below zero.

• Overbought/Oversold Conditions: The MACD is also can be used as an overbought/oversold indicator. If the shorter moving average pulls away dramatically from the longer moving average and the MACD rises it is likely that the security price is overextended and will soon return to more realistic levels.

• Divergences: Expect the end a current trend may be near when the MACD diverges from the price of a security. A bearish divergence occurs when the MACD is making new lows while prices fail to match these lows. Likewise, a bullish divergence occurs when the MACD is making new highs while prices fail to follow suit. Both of these divergences are most significant when they occur at relatively overbought/oversold levels.