Correlated Currency Pairs

Currency correlation measures how pairs move in relation to each other. Some pairs move together (positive correlation), while others move opposite (negative correlation). Understanding these relationships helps you diversify risk and avoid unintended exposure.

What is Correlation?

Correlation is expressed as a number between -1 and +1:

Why Correlation Matters

Risk Management

Trading correlated pairs multiplies your exposure:

Example:

• You buy EUR/USD (1 lot)
• You buy GBP/USD (1 lot)
• Correlation: +0.68 (ten-year measured average)

Your USD short exposure is 2 lots notional, and at +0.68 the two positions together swing like about 1.83 lots of a single pair (√(1 + 1 + 2 × 0.68)), not 1. If USD strengthens, both trades lose.

Portfolio Diversification

Understanding correlations helps you:

• Avoid doubling risk accidentally
• Find truly diversified trades
• Balance your portfolio

Trade Confirmation

Correlations can confirm trades:

• If you're bullish EUR/USD
• And GBP/USD is also rising
• Confirms USD weakness thesis

Strongly Correlated Pairs

Positive Correlations (Move Together)

Negative Correlations (Move Opposite)

AUD/USD and NZD/USD: The Twins

These pairs have ~90% positive correlation:

Why So Correlated:

• Geographic neighbors
• Both commodity exporters
• Similar economic structures
• China exposure
• Risk-on/risk-off behavior

Trading Implication:

• Never trade both in the same direction
• Same as doubling your position
• Choose one, not both

EUR/USD and USD/CHF: The Mirror

These pairs have a strong negative correlation (about -0.76 measured over ten years; -0.90 is often quoted):

Why Inverse:

• Both EUR and CHF are European
• CHF often follows EUR
• USD is common denominator
• When USD weakens, both EUR and CHF strengthen

Trading Implication:

• Don't go long both
• Don't go short both
• Positions would offset each other

Using Correlations in Trading

Confirmation

Before entering a trade:

1. Check correlated pairs
2. Are they supporting your view?
3. EUR/USD bearish? Check if USD/CHF is bullish
4. Confirmation increases confidence

Hedging

Use negative correlations:

• Long EUR/USD
• Long USD/CHF as partial hedge
• Movements offset somewhat

Avoiding Doubling Risk

Before adding positions:

1. Check existing exposure
2. Calculate correlation
3. Assess total effective position

Example Assessment:

Current: Long EUR/USD 1 lot
Considering: Long GBP/USD 1 lot
Correlation: +0.68 (ten-year measured average)
Exposure: 2 lots short USD notional (about 1.83 lots-equivalent in volatility)
Decision: pairs correlated at 0.50 or more share 1.5% combined risk, so skip it or split the risk between them

Finding Opportunities

When correlations break down:

• Normally correlated pairs diverge
• May indicate upcoming movement
• One pair may be "wrong"
• Opportunity to trade the convergence

Correlation Changes Over Time

Correlations aren't fixed:

Short-term Changes:

• News events affect individual pairs
• Correlations weaken temporarily
• Return to normal after event

Long-term Changes:

• Economic relationship changes
• Central bank policy divergence
• Structural economic shifts

Example: EUR/USD and GBP/USD correlation weakened during Brexit as GBP moved on UK-specific factors.

Checking Correlations

Online Tools

Many websites offer correlation matrices:

• Free calculators available
• Show current and historical correlations
• Compare multiple pairs

Calculate Yourself

If you have data:

• Use spreadsheet correlation function
• Compare price changes, not prices
• Use 20-100 period samples

Platform Indicators

Some platforms offer:

• Correlation indicators
• Matrix displays
• Alert when correlations change

Correlation-Based Strategies

Pairs Trading

Trade the relationship between two pairs:

1. Identify normally correlated pairs
2. Wait for divergence
3. Buy the underperformer
4. Sell the outperformer
5. Profit when they converge

Basket Trading

Trade multiple pairs for one thesis:

• Bearish USD?
• Buy no more than two USD pairs, e.g. EUR/USD and AUD/USD
• Diversified USD short
• Our caps: no single currency above 2× exposure; pairs correlated at 0.50+ share 1.5% combined risk

Hedged Portfolios

Balance positive and negative correlations:

• Long EUR/USD
• Long USD/JPY
• Partially offsetting USD exposure

Common Correlation Mistakes

Ignoring Correlations: Trading multiple pairs without checking relationships.

Assuming Correlations Are Fixed: They change over time.

Over-Hedging: Fully inverse positions cancel out entirely.

Confirmation Bias: Only looking at correlations that support your view.

Forgetting During Stress: Correlations often increase during crises—everything moves together.

Key Correlation Relationships

Strong Positive:
EUR/USD ↔ GBP/USD ↔ AUD/USD
AUD/USD ↔ NZD/USD (very strong)
EUR/JPY ↔ GBP/JPY

Strong Negative:
EUR/USD ↔ USD/CHF
GBP/USD ↔ USD/CHF

Key Takeaways

• Correlation measures how pairs move relative to each other
• +1 means perfect together; -1 means perfect opposite
• AUD/USD and NZD/USD are highly correlated (~90%)
• EUR/USD and USD/CHF are strongly inverse (-0.76 measured over ten years; the -0.90 usually quoted is too strong)
• Trading correlated pairs multiplies your risk
• Correlations change over time—check regularly
• Use correlations for confirmation and risk management

What's Next?

Learn about safe-haven currencies and their behavior during market uncertainty.

This article is for educational purposes only and does not constitute financial advice.