Systematic Macro funds use quantitative (number based) models to try to predict changes in the prices of assets. The system generates the investment ideas. These models are trying to take advantage of market inefficiencies that arise because we humans don’t always invest rationally. Some of these strategies will be trend following. For example, investing on the lines that if the value of one currency has fallen relative to the value of another for three straight days, it is likely to do so for a fourth.