Put EUR/USD and GBP/USD on the same chart and for long stretches they look like one line drawn twice. That is not a coincidence, and understanding why tells you something important about what a master who trades both is really doing.
The common denominator
Both pairs have the US dollar as the quote currency. When the dollar strengthens, both pairs fall, because a euro and a pound each buy fewer dollars. When the dollar weakens, both rise. Most of the daily movement in either pair is dollar movement, and the dollar moves on US data, Fed expectations and global risk appetite — none of which has anything to do with Europe or Britain specifically.
Over long periods the correlation between the two pairs sits around 0.8–0.9, which is very high. On a US inflation surprise it is close to 1.0 for the hour: both pairs jump the same direction at 13:30 GMT by roughly the same amount, because the only thing that changed was the dollar.
When they split
The two pairs diverge when the news is about the euro or the pound rather than the dollar. Some recurring causes:
- Central bank divergence. If the European Central Bank is cutting rates while the Bank of England holds, the pound gains on the euro, EUR/USD lags and GBP/USD leads. This is the most common source of a multi-week split.
- UK-specific shocks. Political events, a budget, a gilt-market wobble — the pound reacts, the euro largely does not. GBP/USD can fall 2% on a day EUR/USD is flat.
- Eurozone data. German industrial numbers, eurozone inflation, an Italian political headline. EUR/USD moves; GBP/USD watches.
- Risk appetite. The pound behaves slightly more like a "risk" currency than the euro does. On sharp equity sell-offs GBP/USD tends to fall harder.
The pair that captures the split directly is EUR/GBP. If EUR/USD and GBP/USD are moving apart, EUR/GBP is trending; if they are moving together, EUR/GBP is going nowhere. Traders who want to bet on Europe versus Britain without a dollar view trade EUR/GBP for that reason.
What this means for a copied portfolio
Here is the practical point. Suppose you follow two masters. One trades EUR/USD, the other GBP/USD. You feel diversified. On most days you are not: when the dollar rises, both of your copies lose at the same time, and when it falls, both win. Your two positions are close to one large dollar position.
That is not necessarily bad — you may want dollar exposure — but you should know it. The same logic applies to a single master who is long both pairs at once: they have not spread their risk, they have doubled one bet. When you look at a master's Recent Trades, notice whether their EUR/USD and GBP/USD trades are open at the same time and in the same direction. If they are, treat the position as one.
Reading a divergence on a profile
A master who trades both pairs and shows steady returns through a period when the two diverged sharply is showing you something: they were trading the individual currencies, not just the dollar. A master whose good months coincide exactly with dollar trends and whose bad months coincide with dollar reversals is, in effect, running one strategy — a dollar strategy — and their drawdown will reflect how well they handle dollar turning points.
Neither is wrong. The first is harder and rarer; the second is honest work if the drawdown is controlled. What you want to avoid is paying for "diversification" that is one trade wearing two names.
Correlation is not constant
The 0.8–0.9 figure is an average, and averages hide the interesting weeks. During a pure dollar move — a Fed repricing, a risk shock — the two pairs are near-identical and the correlation touches 0.95. During a Bank of England meeting week it can drop below 0.5 for days as the pound trades on its own news. A master who claims to trade "the majors" is, in the first kind of week, trading the dollar once; in the second, trading two different things. The profile cannot tell you which week it was, but the calendar can: if the BoE and ECB both met and the pairs still moved as one, the master's edge was a dollar view, whatever the trade list says.
The same warning applies to USD/CHF, which moves almost exactly opposite to EUR/USD because the franc and euro are tightly linked. A master long EUR/USD and short USD/CHF at the same time has doubled a single position, not hedged it.
A small experiment
On the terminal, open EUR/USD and GBP/USD on the daily chart and look at the last three months. Count the days the candles were the same colour. Then look at EUR/GBP for the same period. Where EUR/GBP made a big move, you will find the days the two dollar pairs disagreed. Ten minutes of this and you will never again mistake two dollar pairs for two independent bets.
EUR/USD and GBP/USD share a dollar. Most days they are one trade. The days they part are about Europe or Britain — and EUR/GBP shows you which.
This article is education, not investment advice. Trading and copy trading in leveraged instruments carry a high risk of losing the funds you allocate. Read the Risk Disclosure.