The MACD is constructed based on a series of moving averages and how they relate to one another. The standard MACD looks at the relationship between a currency pairs 12-period and 26-period exponential moving average. Specifically, the MACD looks at the distance between these two moving averages. If the 12-period moving average is above the 26-period moving average, the MACD line will be positive. If the 12-period moving average is below the 26-period moving average, the MACD line will be negative. The MACD line is accompanied by a signal line. This line is a 9-period exponential moving average of the MACD line.