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September 21, 2026

Macro Research · Bank of Japan · September 2026

Japan's Savings
Start to Stay Home

The Bank of Japan's September hike was priced, and markets read it as dovish. The effects on global yields, yen carry and risk assets run through slower channels.

Bank of Japan head office, Tokyo. Photo: Maciej Janiec, licensed under CC BY-NC-SA 2.0.

Priced in, with the effects still to come

A 25-basis-point hike, 7–2

The board voted on September 18 to guide the uncollateralized overnight call rate to around 1.25 percent, up from around 1.0 percent, effective September 24. The complementary deposit facility rate, the basic loan rate and the statutory basic discount rate moved with it, as Table 1 shows, and the board unanimously changed loan terms on several funding operations.

Governor Kazuo Ueda, Deputy Governors Ryozo Himino and Shinichi Uchida, and board members Hajime Takata, Naoki Tamura, Junko Koeda and Kazuyuki Masu voted in favor. Toichiro Asada dissented. Core consumer price index (CPI) inflation, which excludes fresh food, had recently run below 2 percent, and he judged that economic strength was not assured, so he preferred to keep the old guideline. Ayano Sato also dissented: in her judgment, economic and price developments had not accelerated enough to justify a hike at this meeting.

Takata and Tamura objected from the other side, though only to the wording of the outlook report: each judged that inflation, underlying inflation included, was already broadly consistent with the 2 percent target.

The BOJ described the economy as having recovered moderately, with pockets of weakness and an impact from the Middle East situation, and expects moderate growth supported by government measures and rising global demand tied to artificial intelligence (AI), despite high crude prices. Producer prices are high, and wage and cost increases are passing into retail prices. The bank projected CPI excluding fresh food clearly above 2 percent from the second half of fiscal 2026, easing toward 2 percent later in the July forecast horizon, with underlying inflation consistent with the target between the second half of fiscal 2026 and fiscal 2027. It listed the Middle East, global AI demand and foreign-exchange moves as risks, and named the chance that underlying inflation overshoots 2 percent.

That guidance depends on economic activity, prices and financial conditions, and the BOJ said timing and pace would follow how closely the baseline and its risks play out. It added that financial conditions would remain accommodative after the hike, with real interest rates still low and corporate funding conditions favorable. By its own account, the September move tightens policy at the margin without making it restrictive.

A dovish reaction to a hawkish move

The dollar rose as much as 1.3 percent to 158.05 yen after the announcement, then gave back part of the gain on reports that Japanese authorities had conducted rate checks. Late in the global session it stood near 156.73 to 156.76, about 0.5 percent higher on the day. Bond yields moved with the currency. The 10-year JGB yield fell roughly 4.9 basis points to 2.947 percent and the two-year fell about 2.5 basis points to 1.835 percent. CNBC's headline said Japan's markets had flipped the usual script. Traders priced the two dissents and the missing signal for October; the hike itself was already in prices.

The Nikkei 225 gained about 1.5 percent, though sources put the gain between 1.38 and 1.70 percent depending on the timestamp. TOPIX rose only about 0.2 percent, a gap that points to a narrow rally weighted toward exporters and technology names, helped by the weaker yen and lower yields.

Elsewhere the moves were small (Figure 1). Fed policy, energy prices and sector rotation were all in play that day, so none of them isolates the BOJ.

Figure 1. Market moves on September 18, 2026

Sources: Reuters, CNBC, Investing.com, Pip Theory. Observation windows differ by instrument (Tokyo close, late global session, US close), and some moves are approximate as reported. Red bars are Japan-linked; the USD/JPY peak is intraday.

Bitcoin's reading depends on the clock. CoinDesk had it near $76,900 and broadly steady just after the announcement. Reuters later reported a 6 percent gain to about $81,000 in the New York session, by which time global liquidity, oil and US risk sentiment had also shifted. We would not credit that move to the BOJ.

September shows why the sign of a rate move is a poor guide to its effect. Markets price the surprise and the expected path. A dovish hike delivers the expected increase and leaves the path less threatening, and September had those features even though the formal guidance points to further tightening.

The question for December

Analysts split on how much weight the two dissents deserved. TD Securities' Prashant Newnaha called the commitment to keep raising rates, together with the warning about upside inflation risk, hawkish, yet found no evidence pointing to an October move. HSBC's Fred Neumann said the statement and the dissents left doubt about the board's appetite for tightening quickly. He thought consecutive hikes unlikely but said the BOJ had to keep December open, particularly with the Federal Reserve also leaning hawkish.

Nomura's Naka Matsuzawa attributed the yen's decline to the dissents and argued the BOJ could hold the market's roughly quarterly pricing without naming October. Daiwa Securities' Yugo Tsuboi called the decision dovish: no 50-basis-point option had materialized, and the dissents made rapid acceleration harder to imagine. Less fear of over-tightening, he judged, supported equities.

Two other houses read the meeting as one step in a wider shift. Masahiko Loo of State Street Investment Management described Japan as part of a synchronized tightening cycle in which higher domestic yields keep more capital at home. The issue he sees is Japan gradually ceasing to be the marginal buyer of foreign assets, while existing holdings stay put. Invesco's David Chao made a related point about regimes: the BOJ was no longer an extreme outlier, with the BOJ, the Fed and the European Central Bank (ECB) all tightening in the same month.

Published forecasts cluster around a roughly quarterly rhythm. Goldman Sachs called the 25-basis-point move before the meeting and argued that a 50-basis-point hike, or hikes at both the September and October meetings, would need clearer evidence of inflation overshooting. Vanguard's international rates team sees 2 to 2.5 percent as a plausible neutral rate, above what markets were pricing at the time.

As of September 21 we found no assessment of the decision from the International Monetary Fund (IMF). Its baseline is the April 2026 Article IV consultation and Global Financial Stability Report (GFSR), which backed gradual, data-dependent hikes toward a neutral rate and close monitoring of JGB market functioning, and which estimated that the BOJ's balance-sheet reduction would add about 9 basis points to JGB term premia in 2026.

From policy to portfolio

A rate rise in Tokyo reaches portfolios elsewhere by five routes (Table 3). The first three can hit within days if positioning is stretched; the last two work over quarters and years.

A simplified return on an unhedged, yen-funded carry position shows why the first three channels interact:

Here (i_A − i_JPY) is the interest-rate differential, R_A the local-currency return on the acquired asset, Δs_JPY the yen's appreciation against the asset currency, and C the combined transaction, hedging and financing costs. A BOJ hike raises i_JPY directly. If it also lifts the yen or foreign-exchange volatility, several terms worsen at once, and the adjustment arrives as a jump.

The academic literature on carry trades predicts that asymmetry. Brunnermeier and co-authors (2008) found that high-interest-rate investment currencies show negatively skewed returns, because positions come off abruptly when risk appetite and funding liquidity fall, and that rises in the VIX coincide with carry losses. What matters is the interaction among exchange rates, leverage, margin requirements and volatility, and a 25-basis-point change in funding cost is a small part of it.

The Carry Trade's Realistic Figure

Nobody has a clean count of the yen carry trade. Positions sit in cash borrowing, futures, forwards, swaps, options, offshore securities and inter-office bank flows, so each statistic captures a slice, and the published figures differ by nearly an order of magnitude because they measure different things.

The BIS estimated carry exposures at roughly ¥40 trillion, or $250 billion, entering the August 2024 turbulence and warned that data gaps probably biased the figure down. It separately counted about ¥40 trillion of yen loans to nonbanks outside Japan and more than ¥80 trillion of cross-border yen bank claims on nonbanks in offshore centers. The Jefferies analysis of BIS data put total cross-border yen borrowing at a record ¥360 trillion, about $2.35 trillion, by March 2026.

How much of that ¥360 trillion is still exposed to a rapid yen rise? No source we found says. The total includes financing that has nothing to do with directional bets, and the leveraged, unhedged, volatility-sensitive slice is the hardest part to observe. For carry specifically, the BIS's roughly ¥40 trillion is the only published figure. It dates from 2024, and the BIS itself thought it low. We treat the vulnerable stock as unmeasured.

The cost of the shrinking subsidy is easier to size. Each 25 basis points on the overnight rate adds about ¥100 billion a year in interest on ¥40 trillion of yen funding, and about ¥900 billion on the full ¥360 trillion if all of it repriced with the overnight rate, which it does not. These are Icarus Asia's arithmetic bounds on carrying cost. They say nothing about losses from a yen rally, which arrive faster than interest costs do.

August 2024 is the nearest thing to an event study. A hawkish BOJ increase and weak US labor data landed together. TOPIX fell 12 percent in one day, the S&P 500 lost 3 percent on August 5, the VIX briefly rose above 60, and equities fell across Europe and Asia. Markets recovered quickly, which tells us the episode amplified a shock and did not reveal a deteriorating outlook. The BIS attributed the amplification to high leverage, thin August liquidity, rising margins and strategies built on low volatility. Initial margins at the Japanese clearing house rose 60 to 80 percent on long equity-index positions and 43 percent on short JGB-futures positions, which forced more selling. Among major high-yield currencies the Mexican peso fared worst, followed by the Brazilian real and the South African rand.

Before this meeting, Reuters reported on September 8 that the yen had gained 4.5 percent in a week and that three-month USD/JPY implied volatility had recorded its largest weekly rise in two years. Analysts quoted there warned that residual yen shorts could feed a self-reinforcing unwind if appreciation triggered stops and deleveraging. The hike, read as dovish, pushed the yen the other way and took the acute risk down. Structurally, nothing changed: each further hike narrows the carry, and a sudden yen rally hurts leveraged holders more than proportionally.

A calm reaction carries a cost of its own. The BIS found leveraged positions being rebuilt soon after the 2024 turbulence and concluded that only part of the low-volatility, cheap-yen trade had been unwound. Low volatility after an expected hike may postpone tail risk without removing it.

Where the money goes from here

Japan's international investment position gives the scale. At the end of 2025 external assets stood at about ¥1,806 trillion against liabilities of about ¥1,244 trillion, leaving net assets of about ¥562 trillion. Outward portfolio assets, the part most open to reallocation, came to about ¥769 trillion: roughly ¥401 trillion in equities and fund shares and ¥368 trillion in debt securities. The IMF put Japan's net foreign assets at $3.7 trillion in the third quarter of 2025 and its 2025 current-account surplus at 4.8 percent of gross domestic product (GDP).

Figure 2. Japan's external assets by component, end-2025 (¥ trillion)

Source: Ministry of Finance, International Investment Position of Japan (end of 2025). The residual bar is Icarus Asia's calculation: total external assets less direct investment, portfolio investment and reserve assets. Portfolio bars in red.

Treasuries are the visible test. Japan held about $1.10 trillion in July, still the largest foreign holder, down from about $1.21 trillion in April, a fall of about $106 billion, with a decline in each of the three months since. TIC compiles holdings from US custodians and broker-dealers, so it cannot always identify the ultimate owner or separate valuation changes from sales. July was the latest month published, and August country data had not been released by September 21.

Figure 3. Japan's holdings of US Treasury securities, April to July 2026 ($ billion)

Source: US Treasury, TIC Table 5, Major Foreign Holders of Treasury Securities. Custodial data; changes combine transactions and valuation effects. The vertical axis is truncated. Exact values in the Data Appendix.

Flow data need more care than holdings data, because the sources disagree and cover different things. The Ministry of Finance (MOF) series counts Japanese debt securities and not JGBs alone, and only designated reporting institutions. Reuters applies its own classification, and the Japan Securities Dealers Association (JSDA) splits flows by maturity. On the MOF series, nonresidents were net sellers in August 2026 of about ¥0.7 trillion of long-term debt and about ¥5.0 trillion of short-term debt. On Reuters' broader count, foreigners were net buyers of about ¥3 trillion of Japanese fixed income in August and about ¥18 trillion over the six months to August. The two August readings disagree in sign, and we would lean on neither.

The longer record is clearer. Nonresidents bought a record ¥13 trillion net of long-dated Japanese bonds in 2025, about 53 percent of all new purchases and the most since comparable data began in 2005, according to the IMF, and they held roughly 13 percent of JGBs in the latest MOF snapshot. JSDA data for July show net foreign sales in two- and five-year debt and net purchases beyond ten years. Any claim about foreign JGB flows means little until it names its source, instrument and maturity.

The flow runs both ways, and that matters for markets. Foreign buying of JGBs can support the yen and tighten conditions for yen-funded positions, while Japanese institutions buying fewer foreign bonds can raise yields abroad.

On the domestic side, the J.P. Morgan Asset Management survey found the highest net share planning to add domestic bonds since it began in 2008, and funds are still cutting overseas debt because currency-hedging costs are high. J.P. Morgan Private Bank expects structural upward pressure across the JGB curve, with normalization supporting shorter yields and higher term premia pressing the long end. Life insurers own 15.8 percent of the JGB market but have been buying less, especially at super-long maturities, because volatility creates balance-sheet risk they do not want. Higher yields lift their reinvestment income but cut market values and add solvency volatility, so their recent pattern has been to swap low-coupon domestic bonds into higher-yielding JGBs. Nippon Life planned about ¥3 trillion of such rotation after about ¥2 trillion in the prior fiscal year, according to the IMF. Pension and insurer behavior plays out over quarters and fiscal years, tied to mandate reviews and annual investment plans.

Our reading of the sequence: smaller overseas reinvestment first, then selective sales of hedged foreign bonds, then larger domestic allocations as mandates come up for review, and broad repatriation last, if it comes at all. The IMF regards abrupt reallocation as unlikely because Japanese institutions hold substantial capital and liquidity buffers and the BOJ owned 51 percent of outstanding JGBs as of June 2025, which limits forced domestic selling. That supports a lasting term-premium effect and argues against reading one BOJ hike as the start of a large liquidation.

The IMF's April 2026 stability analysis named the United States, Australia and several euro-area markets as the most exposed, since Japanese investors hold large shares there, and found that BOJ policy shocks spill over most strongly into foreign sovereign yields where Japanese participation is larger. Vanguard frames the result as Japan becoming a competitor for global capital: higher JGB yields keep more savings at home and push long-term global yields up when sovereign, corporate, AI and defense financing needs are already heavy. The effect is hard to isolate from synchronized global tightening, fiscal issuance, quantitative tightening, oil-driven inflation and AI financing demand.

Asset-class sensitivities

Global equities feel the discount rate first. If higher JGB yields draw Japanese money out of foreign bonds, sovereign yields and term premia rise abroad, which raises the cost of equity and cuts the present value of distant cash flows. A high-frequency study of Japanese policy announcements found that unexpected tightening lowers Japanese stock returns and lifts government-bond yields, more so at longer maturities. Growth and technology shares are the most exposed, both because their value sits in far-off cash flows and because liquid mega-caps get sold first when investors need cash. A decline of about $1 trillion in AI and technology valuations in July and August 2024 preceded the acute unwind. When the BOJ tightens because wages, demand and inflation are strengthening, it also sends a growth signal, and that offsets part of the discount-rate effect. Inside Japan, September's rally alongside a weaker yen shows that the currency and the perceived policy path can outweigh the mechanical effect of the rate.

Investment-grade credit takes its hit through duration: higher risk-free yields lift all-in borrowing costs, with long-dated bonds and frequent issuers the most exposed, while spreads may hold if growth does. High-yield bonds, leveraged loans and collateralized loan obligations (CLOs) face a worse asymmetry. Cross-border yen claims on offshore nonbanks have financed structures including US CLOs, which ties yen funding to credit-market liquidity, so a volatility shock can widen spreads through dealer balance sheets, hedge-fund leverage and forced sales before default rates change. A BOJ hike does not cause defaults. It can raise refinancing costs and set off a liquidity repricing, and weaker earnings or a US recession would compound the two.

The clearest potential losers from a disorderly unwind sit in emerging markets. Academic work on the BRICS economies finds stronger lower-tail dependence between carry returns and equity returns during crises. The IMF's 2026 analysis found emerging-market portfolio flows increasingly weighted toward carry-driven debt and hedge funds more sensitive to emerging-market carry. Exposure depends less on the level of a country's policy rate than on crowded foreign positioning, weak external balances, dependence on imported energy, shallow markets and limited policy credibility. Countries with strong current accounts, credible inflation policy, adequate reserves and little foreign-currency debt should see only temporary outflows. In an orderly normalization the outcome is wider dispersion across emerging markets rather than indiscriminate selling.

Private assets respond with a lag, because appraisals set the marks and financing is often fixed for a period. The economics resemble long-duration public equity and below-investment-grade credit, and steady marks are no evidence of immunity: a sustained rise in sovereign yields cuts transaction volumes, widens bid-ask gaps and delays exits, and floating-rate borrowers, highly levered buyouts and refinancing-dependent strategies face the greatest risk.

Cryptoassets are a tactical case. They trade around the clock, often carry embedded leverage and can be sold when other markets are shut. The 2024 losses of up to 20 percent came from cross-margin liquidation with no direct link to Japanese rates, and September 2026 did not repeat them: Bitcoin was reported higher later that day as the yen weakened and the split vote eased fears of a quick follow-up (section 02 explains why we do not attribute that to the BOJ). Direction depends on the policy surprise, the yen, leverage and global sentiment.

Five developments to monitor

September fits the orderly-normalization row better than the shock rows: the hike was expected, the yen weakened and risk assets absorbed it. The BOJ's stated intention to keep raising rates has still shifted the distribution of outcomes, since markets now have to price a higher chance that Japan's real rate, domestic yields and exchange rate converge on less exceptional levels.

The worst configuration needs the BOJ to tighten, the yen to rise, global growth to weaken and leverage to be crowded, all together. In August 2024 weak US labor news and a hawkish reading of the BOJ jointly triggered the reassessment, and leverage and margins amplified it. In a pure global-inflation scenario the yen might not strengthen enough to force a carry crash, but higher global term premia could still depress bonds and equities at once.

Stabilizers exist, and they matter for sizing the tail. A risk-off episode lowers US and European yields, which widens the yield advantage of foreign bonds over JGBs again and slows Japanese repatriation at the moment markets most need buyers. It can also push the BOJ toward more cautious communication. The quick recovery after August 2024 suggests that markets and policymakers can interrupt a deleveraging spiral before it turns systemic.

Neutral now, more volatile later

We read the September hike as largely a non-event for global risk assets in the near term and the process behind it as a source of higher volatility over a longer horizon. The expected 25 basis points were absorbed, and the split vote led markets to a dovish reading. Yen funding is getting more expensive, JGBs are becoming competitive with foreign assets, and Japan's savings surplus can no longer be assumed to hold global yields down.

Investment-grade credit and broad developed-market equities should hold up better under orderly normalization, and Japanese banks and domestic-value shares may benefit even as exporters face currency risk.

September's opposite reaction rules out any mechanical link between BOJ hikes and global sell-offs. The claim the evidence does support is narrower: normalization removes a long-standing subsidy to leverage and makes asset prices more sensitive to bad news from elsewhere. Gradual normalization should produce rotation, higher term premia and wider dispersion. A rapid yen rally during a global growth scare could restart the leverage, margin and volatility loop seen in August 2024.

The August TIC release will show whether Japan's Treasury holdings, lower in each month since April, kept falling.

What the numbers can and cannot say

Caveats on timing, scope and coverage sit beside the figures they qualify, and exact values are in the Data Appendix.

Attribution. Same-day moves in global equities and crypto coincided with Federal Reserve policy, oil-price changes and Middle East developments. They are reactions observed after the BOJ decision, and they are not estimates of its causal effect.

Sources. Public post-meeting commentary from market strategists was abundant. Full proprietary reports from Goldman Sachs and J.P. Morgan were not publicly accessible, so we relied on public summaries and official publications. Where a figure rests on a Reuters interview or a third-party summary rather than an official release, the source note beside it says so.