Direct relationship: what “related” means here
EUR/USD vs USD/JPY are two major currency pairs that both involve the US dollar, but in different roles.
- EUR/USD compares the euro (EUR) to the US dollar (USD).
- USD/JPY compares the US dollar (USD) to the Japanese yen (JPY).
Because USD appears in both pairs, you can think of them as connected through cross-currency exposure: movements in the USD can affect both pairs, even though the “other currencies” (EUR or JPY) may respond differently.
Mechanics: how the pairs connect
A currency pair price is a conversion rate. When you say “EUR/USD changes,” you are describing how many US dollars you get for one euro. When you say “USD/JPY changes,” you are describing how many Japanese yen you get for one US dollar.
So if the USD strengthens overall against many currencies, you often see:
- EUR/USD tend to fall (USD buys more; EUR buys fewer USD).
- USD/JPY tend to rise (USD buys more JPY).
This is a mechanical linkage through the shared USD, not a guarantee.
Related currencies and a practical way to map them
To understand what is “related” to EUR/USD vs USD/JPY, look at the currencies that sit next to USD in each pair:
- EUR (euro area) is the other currency in EUR/USD.
- JPY (Japan) is the other currency in USD/JPY.
From that perspective, the related currency set is mostly EUR, USD, and JPY. However, real-world FX markets are also influenced by broader cross-currency patterns because traders manage risk across many pairs.
Evidence or example: why historical association can flip
Without using real-time data, you can still reason about possible outcomes.
Example (assumptions stated):
- Assume that at one point, US rates expectations rise relative to both euro-area and Japan-related expectations.
- Traders may increase demand for USD assets.
Under that scenario, the shared-USD mechanism can create consistent historical co-movement between EUR/USD and USD/JPY.
Now consider a different assumption:
- Suppose risk sentiment changes and investors rotate toward or away from EUR or JPY for reasons that do not move USD uniformly.
- Then EUR/USD may not react the same way as USD/JPY.
In both examples, the key limitation is that the pairs are linked through USD, but EUR and JPY can diverge due to their own drivers, so the “relationship” is not stable.
Limitations and failure modes (what can break the relationship)
Several practical issues can make EUR/USD and USD/JPY relationships unreliable:
- Variable drivers: USD can move for US-specific reasons, while EUR or JPY can move for non-US reasons. That changes the joint behavior.
- Costs and execution: Differences in dealing conditions—such as spreads and liquidity—can affect observed movements and short-term behavior. Even when the underlying currencies move similarly, the traded price path can differ.
- Time-varying correlations: Historical co-movement can strengthen or weaken across regimes (for example, calm vs volatile periods). Past association does not imply future association.
- Jurisdiction and platform effects: How prices are displayed, how you access liquidity, and how your account conditions are structured can change what you observe, even if the underlying market economics are the same.
Verification and next question
If you want to independently verify “which markets are related,” you can do it by checking how often and when the two pairs move in the same direction, and how that pattern changes across time windows.
A good next question is: Is the relationship mostly explained by USD strength/weakness, or by EUR-vs-JPY forces that influence one pair more than the other? You can also compare the behavior of a third reference pair (for example, EUR/JPY) to see whether divergence is driven by euro or yen dynamics.
If you want, you can use the related topic: eur usd vs usd jpy explanation, or go deeper into the mechanics of trading metrics like pip value, spread drivers, or economic releases that can affect these pairs.