USD/JPY carry trade — cheap yen, costly dollar and risk

There are positions on the currency market that earn money even when the exchange rate stands still. That is exactly how the USD/JPY carry trade works: you borrow cheap yen, hold the higher-yielding dollar, and every night the interest-rate difference is credited to your account. For many months it can look like free money. The catch is that this strategy “goes up the stairs and down the elevator” — a single day of market panic can wipe out half a year of patiently collected interest. Below I explain where the gain comes from and why its other side can be so brutal.

What is the USD/JPY carry trade, really?

The carry trade is a strategy where you earn on the interest-rate gap between two currencies. The mechanism is simple: you borrow a low-yielding currency and place the capital in a higher-yielding one, pocketing the difference. On the FX market you do not do this through a bank — the structure of the currency pair does it for you. By holding a long position in USD/JPY, you simultaneously “hold” dollars (the higher Fed rate) and are effectively “short” yen (the low Bank of Japan rate). The broader mechanics of the strategy, independent of any specific pair, are covered in the article on what a carry trade is — earning on interest-rate differentials.

Why did this pair become the classic? Because it joins two opposite poles of monetary policy. On one side the Federal Reserve, which through recent years kept rates high. On the other the Bank of Japan, which for over a decade ran an ultra-loose policy — zero, and at times even negative, rates. That chasm in yields is the engine of the whole strategy, and it is precisely why the yen earned its reputation as the classic funding currency.

Why is the yen the funding currency?

The funding currency is whichever one is cheapest to “borrow”. For long years no large economy offered as low a cost of money as Japan. The Bank of Japan held rates near zero to fight years of deflation and revive growth, so capital from around the world was happy to take on yen exposure and place it in higher-yielding assets — in the dollar, but also in commodity currencies and emerging markets.

All of it rests on the divergence between central banks: as long as the Fed keeps rates high and the Bank of Japan keeps them low, the gap works in favour of the dollar holder. So the carry trade is really a bet that this divergence will hold. The fundamental theory explaining why rate differentials drive exchange rates at all is covered in the article on interest-rate parity. If you want to understand how to read signals from both institutions at once, a separate piece on watching the major central banks helps, and on the Japanese side, the profile of Bank of Japan policy and its impact on the yen.

“In a carry trade, you buy a high interest rate currency and fund it with a low interest rate currency. The most popular funding currency has been the Japanese yen.” — Kathy Lien, Day Trading and Swing Trading the Currency Market, John Wiley & Sons, 2016.

How swap interest accrues — a worked example

You receive the daily gain from a carry trade as swap points: an adjustment your broker applies for holding a position overnight. When you hold a long position in USD/JPY under a positive rate gap, the swap is usually in your favour — the broker credits your account. Let us put numbers on it with a concrete, hypothetical example.

Suppose you hold this position for six months and the rate barely moves in that time. On the swap alone you collect somewhere around 2,200–2,300 USD — with no price move at all. That is the appeal of carry — money working in the background, with no need to call the market’s direction. A caveat: the real swap at your broker is often lower than the theoretical rate gap, because part of the margin stays on the brokerage side, and the rates can change from day to day — what to do when your swap changes unexpectedly mid-trade is answered in the piece on why the swap changed in the middle of a position. I describe the accrual mechanism itself in more depth in the piece on how swap works.

Up the stairs, down the elevator — what is the risk?

This is where the harder part begins. The carry trade has a built-in asymmetry: the interest gain drips in slowly and evenly, but the loss can arrive all at once. That happens because the strategy only works in a calm environment. When fear returns to the market — a stock-market crash, a banking crisis, a surprise central-bank decision — investors close risky positions en masse and buy back the yen they had borrowed. That fuels a sharp strengthening of the Japanese currency and a cascading fall in USD/JPY.

The paradox is that the yen, despite its zero rates, is treated as a safe-haven currency. In moments of panic, capital flees into it — much as it flees into the Swiss franc, whose role I describe in the piece on the franc as a safe haven. For the holder of a carry trade this is the worst scenario: exactly when the strategy seems safest, the yen can gain several percent in a single session.

On top of that comes a second threat specific to the yen: intervention. When USD/JPY climbs too high (historically toward the psychological 150–160 levels), the Japanese state can step into the market: the Ministry of Finance takes the decision to intervene, and the Bank of Japan carries it out, buying yen for tens of billions of dollars. The effect can be immediate — the pair drops several hundred pips within hours. For someone who has been collecting interest for a year, one such day can eat most of the accumulated gain.

Does the carry trade make sense for a retail trader?

For a Polish or European retail trader the carry trade is tempting, but it demands a sober look at three things. The first is leverage. Carry on a retail account rests on leverage, so the interest is calculated on the full position value, not on the deposit you put up. That lifts the nominal gain from carry, but it amplifies the loss on a sudden move just as much — which is exactly why the “elevator down” hurts a retail trader more than a large institution.

The second thing is the horizon. The carry trade makes no sense over minutes or hours — the swap point accrues once a day, so this is a strategy measured in weeks and months. The third is calendar awareness: Bank of Japan and Fed decisions, inflation data, signals of possible intervention. These decide whether the rate gap will hold or start to close. The carry trade is also part of a broader risk appetite — in “risk-on” phases it is favoured by exposure to high-yield currencies, as with the Mexican peso.

Your next step with the carry trade

The carry trade is a good lesson that there is no free money on the market — only a premium for risk taken. Before you stake even a single cent on it, take three concrete steps that cost nothing.

1. Check the real swap at your broker. In the USD/JPY instrument specification, find the swap points for a long position and convert them into an annual percentage. Compare it with the Fed–Bank of Japan rate gap — you will see what share of the theoretical carry you actually receive, and how much stays with the broker.
2. Add both banks’ meetings to your calendar. Mark the next decision dates for the Fed and the Bank of Japan. For each, note what the market expects — this trains you to see the rate gap as the engine of the strategy rather than a single headline.
3. Trace the USD/JPY chart through years of market stress. Open the daily timeframe and find the sessions where the pair fell several hundred pips in one day. See for yourself how quickly the “elevator” wipes out months of slow carry — that intuition is worth more than any table.