Yen falls to 40-year low: global capital flows and asset allocation logic reshaped

Introduction

The yen-to-dollar exchange rate once again approached a 40-year low at the start of this week, hitting 161.60, prompting emergency consultations between Japan's Ministry of Finance and the U.S. Treasury. Despite previous rate hikes by the Bank of Japan and multiple interventions by the Ministry of Finance, the yen's weakness remains unchanged. Asian currencies depreciated in tandem, with the won falling below the 1,500 mark and Asia-Pacific stock markets generally under pressure. This article analyzes the structural factors behind the yen's weakness and its impact on medium- to long-term investment strategies from the perspectives of global capital flows, asset allocation, and interest rate cycles.

Market Background

Interest Rate Divergence and Policy Dilemma

The core driver of the yen's sustained weakness is the interest rate differential between the U.S. and Japan. The Federal Reserve maintains high interest rates, while the Bank of Japan, even after ending negative rates in March, has kept its policy rate at only 0.25%, far below that of the U.S. In June 2026, the yield on 10-year U.S. Treasuries stabilized around 4.5%, while Japan's 10-year government bond yield was only 0.9%, with a spread exceeding 360 basis points, driving sustained carry trade outflows from the yen.

Japan's Ministry of Finance has intervened multiple times in the foreign exchange market since April, but with limited effect. On June 23, Japan's Finance Minister held an online meeting with the U.S. Treasury Secretary to discuss global financial conditions, which the market interpreted as a signal of possible joint intervention. However, the yen only rebounded briefly before weakening again. Japan's core CPI rose 2.1% year-on-year in May, still above the central bank's target, but slowing economic growth (first-quarter GDP contracted at an annualized rate of 0.5%) limits the room for further rate hikes.

Asian Currency Depreciation in Tandem

The South Korean won fell to 1,500 won per dollar, with the Finance Minister calling it "excessive volatility." The KOSPI index plummeted 6% on the day, triggering a temporary trading halt. The MSCI Asia Pacific Index (ex-Japan) fell 1.5%. Japan's Nikkei 225 index pulled back 1.2% after an eight-day winning streak. Risk aversion among global capital intensified, and the U.S. dollar index strengthened to around 106.5.

Current Capital Flows

U.S. Dollar Assets in High Demand

The depreciation of the yen and Asian currencies has enhanced the appeal of U.S. dollar assets. Since late 2025, global institutional investors have significantly increased allocations to U.S. Treasuries and technology stocks. According to JPMorgan's June 2026 fund flow report, inflows into U.S. equity funds over the past two months exceeded $80 billion, with AI-related sectors accounting for nearly 40%.

Emerging Markets Under Pressure

Beyond Japan and South Korea, Southeast Asian currencies such as the Thai baht and Indonesian rupiah have also weakened, with net outflows from foreign capital in Asian emerging market bond and stock markets. The Indian rupee remained near historic lows, but thanks to resilient domestic demand, Indian stocks received some support from local funds.

Commodity Market Divergence

Brent crude edged down 0.4% to $77.56, as the U.S. granted a 60-day waiver on sanctions against Iranian oil, increasing supply expectations. Prices for energy transition-related metals (copper, lithium) remained relatively stable, reflecting long-term demand expectations.

Investment Logic Analysis

The End of Carry Trade?

The yen's depreciation has driven a massive carry trade: investors borrow cheap yen and invest in high-yield dollar assets.The yen depreciation has driven a massive carry trade: investors borrow cheap yen and invest in high-yield dollar-denominated assets. However, as the yen approaches extreme lows, the risk of Bank of Japan intervention rises, increasing carry costs. Once the yen rebounds, it could trigger large-scale unwinding, shaking global markets.

Response Strategies of Institutional Investors

Large asset management firms are gradually reducing direct exposure to yen-denominated positions. BlackRock's Q2 2026 allocation report shows a downgrade of Japanese equities from "overweight" to "neutral," while increasing holdings of dollar-denominated infrastructure and private credit. Pension funds and sovereign wealth funds manage currency risk through hedging instruments.

In the long term, the depreciation trend of Asian currencies may prompt institutional investors to reassess regional asset weights. McKinsey's 2026 Global Capital Flows report notes that multinational corporations are accelerating the diversification of production from China to Southeast Asia, but currency volatility could dampen profits, necessitating the integration of currency hedging strategies.

Structural Drivers

• Slow economic transformation in Japan: Although the new orders sub-index of the Manufacturing PMI hit a four-year high, the overall economy remains reliant on exports with weak domestic demand, making it difficult to support the yen.
• Fed policy dominance: As long as U.S. inflation remains sticky and the Fed maintains high interest rates for an extended period, the interest rate differential will continue to drive the carry trade.
• Geopolitical risk premium: The temporary easing of tensions in the Middle East (sanctions exemption for Iran) briefly lowers oil prices, but global supply chain restructuring and Asia's security situation still lead capital to favor safe-haven assets.In the next 3-10 years, yen weakness may become a structural trend unless Japan significantly improves productivity or changes deflationary expectations. Global capital allocation will shift from "chasing yield" to "managing exchange rate risk."

• Asset allocation direction: Institutional investors may increase allocations to real assets (infrastructure, real estate) and inflation-linked bonds to hedge against currency depreciation.
• Regional diversification: Emerging markets are diverging: Vietnam and India benefit from supply chain relocation, but require currency stability; Latin America (Brazil, Mexico) attracts capital due to resource exports and interest rate advantages.
• Thematic investing: Energy transition and AI investment remain long-term themes, but need to be considered in conjunction with regional currency costs. Japan has advantages in energy transition materials (advanced batteries, semiconductors), but exchange rate risks need to be covered.

The International Monetary Fund (IMF), in its April 2026 World Economic Outlook, warned that disorderly depreciation of Asian currencies could disrupt trade and financial stability. For long-term investors, actively managing currency exposure and diversifying regional risk are the core of the strategy.