Currency correlation
Family VII · Market & styles
Not to be confused with forex currency trading.
Currency correlation quantifies the tendency of two currency pairs to move together or in opposite directions. It is calculated from historical price changes and reported as a correlation coefficient, where +1 indicates perfect positive movement, -1 perfect negative movement, and 0 no linear relationship. Traders and analysts use it to assess diversification, hedge exposure, or avoid concentrated risk.
Calculation and interpretation
The most common measure is the Pearson correlation coefficient, computed from daily or weekly percentage changes in the two pairs' exchange rates over a chosen lookback window. The result ranges from -1 to +1.
- Positive correlation: pairs tend to move in the same direction. Example: EUR/USD and GBP/USD often show positive correlation because both are quoted against the US dollar.
- Negative correlation: pairs tend to move in opposite directions. Example: EUR/USD and USD/CHF often show negative correlation.
- Near zero: no consistent linear relationship.
Correlation is not static; it can change with market conditions, economic cycles, and central bank policies. The lookback period and data frequency affect the value, so different sources may report different figures.
Worked example
Suppose an analyst calculates the correlation between daily percentage changes of EUR/USD and GBP/USD over the past 30 trading days.
The result indicates a very strong positive correlation over the period. If the lookback window were changed to 90 days, the coefficient might differ, reflecting shifting market dynamics.
Practical considerations
Correlation does not imply causation and should not be used alone for trading decisions. It is backward-looking and can break down during periods of stress or regime change. Traders often monitor rolling correlations to detect shifts. For risk management, combining highly correlated pairs can increase portfolio volatility rather than diversify it.
Often confused with
- forex currency trading
- Forex currency trading is the act of buying and selling currency pairs, whereas currency correlation is a statistical measure of how two pairs move relative to each other; the visible sign is that trading involves transactions and positions, while correlation is a calculated number between -1 and +1.