Do trade balances actually move currencies?
The intuitive story is that a country which exports more than it imports sees demand for its currency and therefore a stronger exchange rate. The intuition is not wrong so much as wildly out of scale, and correcting the scale is one of the most clarifying things you can do in this subject.
The identity first
Every country's international accounts must balance:
current account + capital account + financial account + errors and omissions = 0
A current-account deficit is, by construction, financed by a net inflow on the financial account. This is an accounting identity, not a causal claim. It is equally true to say "the United States runs a deficit and must attract capital" and "the world wants to hold dollar assets, so the United States must run a deficit." Serious economists disagree about which way the causation runs, and a course that pretended otherwise would be lying to you.
Now the scale
The BIS triennial survey put global FX turnover at about $9.6 trillion per day in April 2025, up from $7.5 trillion in April 2022. Of that, spot was roughly $3.0 trillion and FX swaps about $4.0 trillion a day.
World trade in goods and services runs on the order of $30 trillion a year. Divide:
30,000,000,000,000 / 9,600,000,000,000 ≈ 3 days
A whole year of world trade is about three days of FX turnover. On any given day, trade-related flows are a rounding error on the tape. What dominates is financial activity: portfolio investment, hedging, dealer intermediation, and the rolling of FX swaps.
So where does the trade balance matter?
In stocks, not flows. A country that runs a current-account surplus every year for thirty years accumulates an enormous net claim on the rest of the world; a country that runs deficits accumulates the mirror liability. Japan was the world's largest net creditor nation for 34 years, until the 2024 figures published in May 2025 put Germany first. The United States is the largest net debtor.
Those stocks matter in three ways:
- Income and repatriation. A large net foreign asset position generates income that may be brought home, and can be brought home fast in a crisis — one of the mechanisms behind yen strength in stress, which Unit 4 unpacks.
- Hedging demand. Pension funds and insurers with big foreign portfolios run currency hedges, and changes in hedge ratios move far more money than the underlying trade ever does.
- Vulnerability. A country financing a large deficit with short-term portfolio inflows is exposed to those flows stopping — the classic emerging-market crisis mechanism.
The other flows on the tape
Worth knowing by name, because they explain moves that look inexplicable: index rebalancing when a bond or equity index adds a country; reserve accumulation or decumulation by central banks and sovereign wealth funds; month-end and quarter-end rebalancing by fund managers restoring benchmark weights; and corporate M&A, where a single cross-border acquisition can require a genuinely large one-way conversion.
The honest summary
A trade surplus is not a reason for a currency to rise this month. It is a slow accumulation of a position that changes how a currency behaves over decades and, especially, how it behaves in a crisis. Confusing the two horizons produces most of the bad currency commentary you will ever read. As always: this is description, not forecast, and nothing here is advice.
In the data
Trade balances are published once a year per country. Below are a persistent deficit economy, the United States, and a persistent surplus one, the euro area: net trade in goods and services, eleven years each, newest first.
One number a year is nothing like an exchange rate's frequency, so any correlation measured between the two is dominated by how you stretched one to meet the other. And the capital-flow side, the half of the balance of payments that actually clears daily, is not published in any series you can set beside a price at all.
Try it now
In the two tables above, mark the years each balance widened and the years it narrowed.
The corresponding pair, EUR/USD, is below at full length. Measure it over each calendar year in the tables, and once across the whole eleven.
- Look for co-movement at a one-year horizon, then at a ten-year horizon. Describe the difference in one neutral sentence, and name one reason the short horizon might show nothing at all.