Bank of Japan rate move: how to spot a carry trade unwind before it hits your Bitcoin holdings

The Bank of Japan raised its key rate by 25 basis points to 1.25 percent on Friday, September 18, 2026. That is the highest level in 31 years. Two days earlier, the US Federal Reserve had lifted its target range by the same amount to 3.75 to 4.00 percent. Two tightenings within three days, and the crypto market is still higher than the day before: Bitcoin was quoted at around $80,978 on the evening of September 18, 5.8 percent above its level 24 hours earlier, with Ether at around $2,613 and a gain of 6.5 percent (own query at CoinGecko on September 18, 2026 at about 18:52 UTC).

The short answer to the question this raises: a rate move by the Japanese central bank is only dangerous for crypto investors if it triggers an unwinding of yen-funded positions. That is precisely what failed to happen this time, and the reason can be read off a handful of figures you can look up yourself. This article explains which ones they are, and what to check on your own position while the tightening round continues.

What the Bank of Japan decided on September 18, 2026

The Japanese central bank raised the uncollateralised overnight call rate from 1.00 to 1.25 percent. The decision appears in the Bank of Japan's overview of monetary policy releases as Change in the Guideline for Money Market Operations under the date September 18, 2026. It is not this year's first move: the same list already shows a change to the same guideline for June 16, 2026. Some media reports on Friday spoke of the first increase of the year, which does not hold up against the central bank's own list of decisions. The defensible wording is the one Al Jazeera also uses: the first increase since June.

The central bank cites persistent inflation as its reason. The core rate of consumer prices in August was close to the target value of two percent. Bloomberg reports that the vote on the policy board was split seven to two; the central bank's own statement does not disclose the split in the publicly linked short version. For the market effect this point matters more than it sounds, and it becomes clear further down why.

What a yen carry trade is and why it moves crypto prices

A carry trade is a transaction in which an investor borrows in a currency with a low interest rate and puts the money into assets with a higher expected return. The yen was the first choice for this for decades, because Japan was the only major industrialised country to keep rates near zero. Anyone funding themselves in yen and investing in US bonds, technology shares or indeed crypto-assets earns on the difference.

The catch lies in the currency. If the yen appreciates, repaying the debt becomes more expensive, regardless of how the asset purchased performs. If the yen rises sharply and quickly, leveraged players have to close their positions to service the funding. What gets sold then is whatever can be sold fastest. Crypto-assets trade around the clock and at weekends, which is why they are regularly hit first in such moments.

A rate move by the Bank of Japan is therefore not in itself a crypto event. It only becomes an event through the exchange rate.

Why the yen fell after the rate increase instead of rising

On Friday the opposite of what the textbook suggests happened. The yen weakened after the announcement. The figures in the reporting diverge: Bloomberg gives a depreciation of 0.8 percent to 157.145 yen per US dollar, while Euronews puts the rate at around 155 yen per dollar. The direction is the same in both accounts; the exact size differs depending on when the measurement was taken.

The reason for the weak currency reaction lies in the two dissenting votes. A split vote tells the foreign exchange market that further moves are contested on the board. The market reads a slower pace into that, and a slower pace means the interest rate gap between Japan and the United States is not closing as fast as an increase on its own would suggest. The carry trade therefore remains attractive on paper, and no pressure to unwind positions arises.

The US and Japan interest rate gap: the figure that shows how sustainable the trade is

The interest rate gap is the distance between the key rate of the country you borrow in and that of the country you invest in. This difference is the most important metric for any carry trade, because it determines the running return on the transaction.

After this week's decisions, 1.25 percent in Japan faces a target range of 3.75 to 4.00 percent in the United States. The gap therefore amounts to 2.50 to 2.75 percentage points, depending on which end of the American target range you take. Both central banks raised by 25 basis points each in the same period, which is why the double tightening left the gap practically unchanged. That is the real news of the week for crypto investors, and it lies not in the level of the two rates but in the difference between them.

Things only become dangerous for leveraged positions once that gap narrows noticeably, that is, when Japan raises while the Fed cuts or pauses at the same time. That constellation was not in place on Friday.

August 2024 as a comparison: how a real unwind could be recognised

The reason a rate decision in Tokyo makes headlines in the crypto industry at all lies a good two years back. In early August 2024 the Bank of Japan raised rates unexpectedly, the yen appreciated strongly, and investors unwound yen-funded positions on a large scale. Bitcoin fell from around $62,000 to about $49,000 within a few days. cryptoticker.io covered the slump as it happened on August 5, 2024; this assessment comes from our own reporting and does not replace external confirmation.

Three conditions were in place at the same time back then: the decision came as a surprise to the market, the yen appreciated markedly, and positioning was heavily leveraged. The decisive difference from today lies in the second point. An appreciation of the yen is the signal that counts, and on September 18, 2026 it did not materialise.

Funding rate and open interest: the market figures that show an unwind first

The funding rate is a balancing payment that flows regularly between the long and the short side in perpetual futures so that the contract price does not detach permanently from the spot price. If it is positive, buyers pay; if it is negative, sellers pay. Open interest denotes the sum of all open contracts and thus measures how much capital sits in leveraged positions in total.

These two values are more useful than any headline, because they show an unwind while it is happening. You recognise an unwind by open interest falling while the price falls: positions disappear instead of merely changing hands. If the funding rate tips into negative territory at the same time, the short side is pushing, and the selling pressure comes from the futures market rather than the spot market. Both metrics are public at the large trading venues, and anyone working regularly with perpetual contracts will also find in our comparison of perp DEX platforms the details of how the individual exchanges calculate this rate and at what intervals it is settled.

On Friday the market showed the reverse picture: rising prices in both major assets. That argues against a forced unwind.

What the rate move means for your leverage and your liquidation distance

For a leveraged position, a rate decision changes two things. First, funding costs rise when the general level of interest rates goes up, for crypto loans as much as for contracts with a funding rate. Second, volatility increases around meeting dates, and higher volatility eats up the distance between entry price and liquidation price faster.

The liquidation distance is the price move your stake can withstand before the exchange closes the position by force. How to calculate it for long and short positions, what role maintenance margin and mark price play, and why isolated margin and cross margin lead to different results is set out in detail in our article on calculating the liquidation price. For this article the practical consequence is enough: if you have not recalculated the distance since the last meeting date, you do not know your risk in the current tightening round.

For retail investors in Germany the room for manoeuvre is limited in any case. Contracts for difference on crypto-assets are subject to a leverage cap of 2:1 in the European Union, a requirement going back to the product intervention measures of ESMA and adopted by BaFin for the German market. Anyone using higher leverage with providers outside that framework loses the regulatory protection and, in the event of a dispute, also carries the risk of having to enforce their claims abroad.

Holding period and loss offsetting: what Section 23 of the Income Tax Act changes in a slump

This is the point at which the macro picture becomes concrete for German investors. Crypto-assets held privately fall under private disposal transactions within the meaning of Section 23 of the German Income Tax Act. A period of one year lies between purchase and sale. If you sell after that, a gain remains tax free.

That rule has a flip side which suddenly matters in a falling market: if a gain is tax free once the one-year period has expired, then a loss after the expiry of the same period can no longer be used for tax either. Losses from private disposal transactions can moreover only be offset against gains from the same category of income, not against salary and not against investment income from a securities account. On top of that comes the exemption threshold: if your total gain from private disposal transactions in the calendar year stays below 1,000 euros, it remains tax free, and once it is exceeded the entire amount is taxable.

No advice to sell anything follows from this. What follows is a check worth doing before the next meeting date brings movement: which of your positions are down, and for which of those does the one-year period expire in the foreseeable future? Anyone who does not document this cleanly cannot prove it later. The tools that track acquisition dates and holding periods automatically and generate a statement for the tax return from them are compared in our overview of crypto tax tools.

Spot holdings and savings plans: why a rate decision usually changes nothing there

For unencumbered holdings in your own custody, a rate decision in Tokyo or Washington changes nothing at all directly. There is no funding that becomes more expensive, no margin to top up and no deadline running out. The price fluctuates, and that is all that happens.

Anyone buying regularly on fixed dates will find the considerations on the meeting day, the execution time and the question of whether pausing before a central bank date achieves anything at all in our article on the Fed rate decision and the Bitcoin savings plan of September 14, 2026. It was written before the September 16 date, and the mechanics it describes still apply unchanged.

The distinction that matters therefore does not run between cautious and bold investors but between funded and unfunded positions. Anyone who has borrowed nothing has nothing to do this week either.

What will make the difference in the coming weeks

The tightening round is not over. The Bank of Japan has signalled that it will continue normalisation, and another meeting date is due for the Fed later this year; the central bank publishes the dates in its public meeting calendar. What is decisive for the crypto side is not who raises by how much, but whether the gap between the two rate levels narrows.

A second signal is the exchange rate. As long as the yen weakens on an increase, the market reads a hesitant pace into it, and the carry trade stays intact. If, on the other hand, the yen starts appreciating markedly on weak US data, exactly the 2024 constellation arises. It is then worth looking at open interest and the funding rate, and doing so before the headlines arrive.

Checking the yen carry trade: what you should take away

1. Recalculate the distance to your liquidation price before the next central bank date. What counts are the maintenance margin, the mark price and the margin mode of your exchange. If you work with perpetual contracts, also compare how the platforms settle the funding rate; the differences are in the perp DEX comparison.
2. Look at which of your positions are down and when the one-year period expires for them. After expiry a loss can no longer be used for tax, and losses from private disposal transactions are only offset against gains of the same kind. A complete statement of acquisition dates is delivered by the tools in the tax tool comparison.
3. Watch the yen exchange rate, not the rate headline. An increase with a falling yen is harmless for the crypto market, a sharp appreciation is the warning sign. Anyone wanting to trade such moves through leveraged products instead of spot should check the terms and the investor protection of the providers beforehand; an overview is in the broker comparison.

The full wording of this week's two decisions is available from the US Federal Reserve and in the Bank of Japan's overview of decisions.

(As of September 18, 2026. This article is not investment advice. Prices and fee structures change; check the terms with the provider before you buy.)