Introduction
For decades, Japan occupied a distinctive position in global financial markets. Its interest rates were exceptionally low compared with those in the United States, Europe and many other developed economies, while the yen was widely used as a funding currency. Investors could borrow yen at relatively low costs, convert the proceeds into other currencies and invest in assets offering higher returns. This strategy became closely associated with the yen carry trade and helped make Japanese monetary policy relevant far beyond Japan’s own economy.
That environment is changing. The Bank of Japan (BOJ) has moved away from the ultra-loose monetary framework that characterized much of the previous decade. In September 2026, the central bank raised its policy rate to 1.25%, according to reporting on the September meeting, while policymakers also discussed the possibility of further increases. The shift matters because the attractiveness of a funding currency depends not only on exchange rates but also on the cost and stability of financing.
Japan is therefore moving into a new phase in which the yen may become a less straightforward source of cheap global funding. That does not mean the yen will suddenly lose its importance or that international investors will immediately abandon Japanese financing. Japan remains one of the world’s largest economies, has deep financial markets, a substantial institutional investor base and a highly developed banking system. However, a sustained rise in Japanese interest rates can change the calculations behind cross-border investment.
The key issue is the narrowing difference between Japanese and foreign interest rates. When Japanese rates were close to zero or below zero, even modest returns available elsewhere could make borrowing yen attractive. As domestic rates rise, the interest expense associated with yen borrowing increases. If the yen also appreciates, investors can face an additional currency loss when converting their foreign assets back into yen.
This combination could gradually reduce the structural advantage that made Japan an important low-cost funding market. It could also affect global bond markets, emerging-market currencies, leveraged investment strategies and the allocation decisions of Japanese institutions.
The change is unlikely to happen in one dramatic event. Instead, it may develop through a series of adjustments in borrowing costs, currency hedging, portfolio allocation and investor expectations. Understanding those channels is important for assessing what the BOJ’s policy shift could mean for international markets.
Why Japan Became a Major Cheap Funding Market
Japan’s role as a funding market was built over many years of exceptionally low interest rates. Following the collapse of its asset bubble in the early 1990s, Japan struggled with weak inflation and periods of economic stagnation. The BOJ responded with increasingly unconventional monetary policies, eventually introducing negative short-term interest rates and extensive purchases of government bonds and other assets.
These policies had consequences well beyond domestic borrowing. When investors can access a currency at a low financing cost, they may use it to purchase assets denominated in currencies with higher interest rates. The basic attraction is straightforward: borrow at a relatively low rate, invest at a higher rate and attempt to capture the difference.
The strategy is known as the carry trade. In the yen carry trade, an investor might borrow yen, exchange those yen for U.S. dollars or another currency and purchase bonds or other assets offering higher yields. The return is not guaranteed because exchange-rate movements can overwhelm the interest-rate advantage. Nevertheless, during periods when the yen remains relatively stable or weak, the strategy can be attractive.
The importance of the yen as a funding currency expanded particularly during periods when the difference between Japanese and overseas interest rates became very large. Reuters reported in September 2026 that estimates based on cross-border yen borrowing pointed to borrowing equivalent to about ¥360 trillion in March, illustrating the enormous scale that yen-based financing can reach when conditions encourage it.
Japan’s domestic financial structure also contributed to this role. Japanese banks, insurers, pension funds and other institutions have historically managed very large pools of capital. With domestic yields relatively low, institutional investors frequently looked overseas for better returns. This produced two related flows: international investors could borrow yen to invest abroad, while Japanese investors could purchase foreign securities directly.
The result was an ecosystem in which Japan’s low interest rates influenced global asset prices. Cheap funding could support demand for foreign bonds, equities, emerging-market assets and other investments. It could also encourage leverage because the financing cost appeared manageable relative to expected returns.
But the same mechanism creates vulnerability when Japanese monetary policy changes. A higher BOJ rate does not automatically unwind every yen-funded position. Investors consider expected returns, currency hedging costs, volatility, liquidity and the outlook for monetary policy. Nevertheless, higher Japanese rates make the starting point less favorable for the strategy.
The distinction between the policy rate and the broader funding environment is also important. Even if the BOJ raises rates gradually, Japanese government bond yields can move considerably as markets anticipate future policy. Reuters reported in late September that Japanese bond yields were still rising after the BOJ’s recent move, while some large Japanese institutions were reducing foreign bond holdings and other major investors remained cautious.
This suggests that Japan’s changing role is not simply a story about one central-bank rate. It is about the repricing of Japanese capital itself.
How BOJ Normalization Changes the Global Carry Trade
The most direct effect of BOJ normalization is an increase in the cost of maintaining yen-funded positions. Suppose an investor previously borrowed yen at a very low interest rate and invested in a foreign asset yielding substantially more. The difference between the two rates created a potential carry return.
If the Japanese funding rate rises, that spread becomes smaller. The investor then has to decide whether the remaining return adequately compensates for currency risk, credit risk, market volatility and financing costs.
The currency channel can be even more important. A carry trade works best when the funding currency does not appreciate sharply. If the yen strengthens, an investor who borrowed yen must eventually repay a larger amount in terms of the foreign currency used for the investment. A position that looked profitable based on interest-rate differences can therefore become unprofitable because of exchange-rate movements.
This is why expectations about BOJ policy can influence global markets before actual rate increases take place. Investors may reduce leverage when they believe Japanese rates are heading higher. They may also buy yen to close short positions. The resulting currency movement can reinforce the incentive for other investors to reduce similar positions.
Reuters noted in September that pressure on the yen carry trade was increasing as expectations for further BOJ tightening grew. The report also highlighted how a surprise BOJ move in 2024 had contributed to a sharp yen move and a broader market selloff.
A reduction in carry-trade activity does not necessarily mean a worldwide financial shock. Investors can unwind positions gradually. Banks can reduce leverage, hedge currency exposure and replace short-term funding with longer-term financing. But if many market participants attempt to exit similar positions simultaneously, liquidity conditions can deteriorate.
The consequences can reach asset classes that have no direct connection with Japan. Investors who borrowed yen to purchase emerging-market bonds may sell those bonds to repay financing. Others may reduce exposure to high-beta currencies. Hedge funds may cut leveraged positions. Banks may reassess foreign-currency lending. These adjustments can produce selling pressure in markets far from Tokyo.
Japanese investors themselves may also change their behavior. When domestic bond yields rise, Japanese institutions no longer need to rely as heavily on foreign assets to obtain income. However, the decision to repatriate funds is not automatic. Currency-hedging costs, foreign yields and expectations about future exchange rates all matter.
This is particularly relevant for life insurers and pension funds. Their investment horizons are long, and their portfolios are governed by liability structures and risk requirements. A gradual improvement in domestic Japanese yields could make some domestic assets more attractive, but global diversification will remain important.
Recent market behavior illustrates this complexity. Reuters reported that Japanese investors had been hesitant to accelerate repatriation because uncertainty remained over where domestic bond yields and BOJ policy would ultimately settle.
Therefore, the BOJ’s policy shift should be understood as a change in incentives rather than a simple reversal of capital flows. Japan may still finance global investment, but the relative advantage of yen funding can become smaller.
Implications for Japan, Global Markets and the Yen
A less accommodative BOJ could have several consequences for Japan’s domestic economy. Higher rates can improve returns for savers and banks, potentially supporting household income and financial-sector profitability. At the same time, higher borrowing costs can place pressure on companies, households and the government, particularly if rates rise faster than economic growth.
The government bond market is especially important because Japan carries a very large public debt burden. Rising yields increase the eventual cost of refinancing government debt, although the effect occurs gradually because existing bonds do not all mature simultaneously. The BOJ therefore has to balance inflation control against financial stability and the broader effects of higher borrowing costs.
For the yen, the relationship with interest rates is not straightforward. Conventional economic theory suggests that higher Japanese rates can support the currency by improving the return on yen-denominated assets. However, the exchange rate also depends on U.S. interest rates, global risk sentiment, energy prices, Japan’s trade position and expectations about future monetary policy.
Current market conditions demonstrate this complexity. Reuters reported on October 1 that the yen remained under pressure against the dollar even as Japanese policymakers were considering additional rate increases, while U.S. Treasury yields were also elevated. This shows that a BOJ tightening cycle does not operate in isolation.
The impact on global bonds may be equally significant. For years, low Japanese yields encouraged investors to search for returns overseas. If Japanese yields become more competitive, some capital could gradually remain within Japan. The potential reduction in foreign demand from Japanese investors could influence markets such as U.S. Treasuries, European government bonds and other developed-market debt.
However, this should not be interpreted as a prediction that Japanese investors will withdraw from foreign markets on a large scale. Institutional portfolios are diversified for structural reasons, and foreign assets provide benefits that domestic securities cannot always replicate. The relevant question is how the marginal allocation changes as Japanese yields become more attractive.
The shift could also affect emerging markets. Many emerging-market currencies benefit from global investors seeking higher yields. If the cost of yen funding increases, some leveraged investors may become more selective. Countries with weaker external balances or higher market volatility could be particularly sensitive to changes in global funding conditions.
At the same time, a gradual reduction in carry-trade activity could improve certain aspects of financial stability if it reduces excessive leverage. Carry trades can amplify market movements when investors are forced to unwind positions rapidly. A more expensive funding environment could discourage some speculative leverage before positions become excessively large.
The BOJ’s September policy decision therefore has implications beyond Japan’s monetary conditions. The central bank’s own policy documents show that monetary-policy adjustments continued through 2026, including changes announced in September and earlier decisions concerning its operations and Japanese government bond purchases.
Another important issue is communication. Markets react not only to the level of interest rates but also to expectations about future policy. If investors believe the BOJ will continue raising rates, Japanese funding conditions can tighten before the next official increase. Conversely, if policymakers signal caution because of weak consumption or external risks, the adjustment can be slower.
The September meeting showed that debate within the BOJ is not one-dimensional. Reuters reported that some policymakers favored a faster move toward higher rates, while others emphasized caution because of weak consumption and uncertainty surrounding the neutral interest rate.
That debate means the future path of Japanese funding costs will depend on inflation, wages, consumption, financial conditions and international developments rather than on a predetermined sequence of increases.
Conclusion
The BOJ’s policy shift represents a significant change in the financial environment that helped make Japan one of the world’s most important cheap funding markets. For many years, extremely low Japanese interest rates encouraged investors to borrow yen and deploy capital into assets offering higher returns elsewhere. That system became an important component of international capital flows and helped establish the yen as a major funding currency.
The move toward higher Japanese interest rates changes the economics of that system. As the BOJ raises borrowing costs, the interest-rate advantage associated with yen-funded investments can become smaller. If the yen strengthens at the same time, the currency risk becomes more significant for investors holding foreign assets financed with yen.
The adjustment could influence hedge funds, banks, institutional investors, bond markets, emerging-market currencies and Japanese asset allocation. It could also encourage some Japanese capital to remain at home as domestic bond yields become more competitive.
Yet the transition is unlikely to be uniform. Japan’s financial institutions have long-standing reasons to maintain diversified international portfolios, while global investors will continue to consider the relative yields available in the United States, Europe and emerging markets. The yen may therefore remain an important funding currency even if its role becomes less dominant.
The most important change may be qualitative rather than absolute. Japan is moving from an environment in which extraordinarily cheap financing was a defining feature of its monetary system toward one in which the cost of yen funding is increasingly determined by conventional monetary and market forces.
The September 2026 policy move, which brought the BOJ’s rate to 1.25%, reinforces that transition. Policymakers have also indicated that further adjustment remains possible, although the pace and timing are subject to economic conditions.
For global investors, the consequence is that Japan can no longer be viewed solely through the old assumption of permanently cheap money. Funding decisions increasingly need to account for Japanese inflation, domestic bond yields, BOJ expectations and yen volatility alongside foreign interest rates.
The global financial system can adapt to this change, but the adjustment may alter where leverage is created, where capital is invested and how investors manage currency risk. As Japanese yields move closer to levels that provide meaningful domestic returns, the yen’s traditional role as a low-cost source of global financing may gradually diminish.
In that sense, the BOJ’s normalization is not simply a Japanese monetary-policy story. It is part of a broader repricing of global capital in which one of the world’s most important sources of inexpensive funding is becoming more expensive and, potentially, more sensitive to conventional market forces.