Correlated positions double the risk without looking like it

[Amanhasnoname]

Opening long EURUSD and long GBPUSD at the same time feels like diversification. In reality, both are short USD, and the combined exposure is close to one trade at double size.

Add a long AUDUSD, and the portfolio is heavily tilted toward a single idea. A sudden dollar rally hits all three at once, and the account suffers a loss far larger than any single stop suggests.

Checking correlations before opening multiple positions is a simple safeguard. A look at recent returns, or simply recognising shared currencies, reveals the overlap.

Some scalpers limit exposure per currency, such as no more than a certain lot count in total USD exposure. Others trade only one pair at a time to keep the picture clear.

Correlation changes through the day, which complicates things. Pairs can move in sync during a dollar-driven session and diverge during local news.

How is exposure to a single currency tracked when trading several pairs?