Buying EUR/USD means buying euros and selling dollars in the same transaction. There is no way to hold a one-sided position in forex, which is why dollar strength shows up across every pair at once.
Pairs are grouped into majors (all involving the US dollar), minors or crosses (major currencies without the dollar) and exotics (a major against a smaller-economy currency). Spreads and overnight costs rise sharply as you move down that list.
The mistake it causes: holding long EUR/USD, GBP/USD and AUD/USD and calling it three trades. It is one short-dollar position at triple size.
Base, quote, and what the number means
In EUR/USD the euro is the base and the dollar is the quote. The price tells you how much of the quote currency one unit of the base is worth. Buying the pair means buying the base and selling the quote simultaneously.
| Group | Definition | Spread |
|---|
| Majors | Anything against USD | Tightest |
| Minors / crosses | Majors without USD | Wider |
| Exotics | Major against smaller economy | Widest, plus heavy swap |
You cannot hold a one-sided position
This is the part that trips people up. Long EUR/USD is short dollars. So is long GBP/USD and long AUD/USD. Holding all three is one short-dollar bet at triple size, which is why dollar strength appears to hit every position at once. It is not bad luck, it is the same trade three times. See correlation.
Exotics cost more in two ways
The spread is structurally wider at every hour, and the interest-rate differential usually means heavy negative swap on one side. A swing position on an exotic can lose more to financing than to the market, which is worth checking before the first trade rather than after the first month.
What to do with this
- Name what each open position is a bet on. If several share the same answer, size them as one.
- Stick to majors while learning. The costs are lower and the behaviour is better documented.
- Check swap before holding anything exotic overnight.
