Summary of Key Points
The Japanese economy is transitioning from being a "global source of cheap liquidity" to normalizing its monetary policy. Over the past 30 years, Japan has relied on ultra-low interest rates to encourage capital outflows (arbitrage transactions), which supported global risk assets. Now that inflation has returned, the central bank is raising interest rates and the yen has depreciated, leading to capital flowing back into Japan. This will impact the demand for U.S. Treasury bonds, global stock markets, and the liquidity of the dollar. Coordination between Japanese and U.S. policies has become a critical factor.
I. Why Was Japan Once a "Global Liquidity Pump?"
Japan's "lost decade" marked the beginning of this trend: After the asset bubble burst in 1989, the economy fell into deflation and low growth. To stimulate the economy, the Bank of Japan (BOJ) lowered interest rates to near zero or even negative levels and purchased a large amount of government bonds (quantitative easing). As a result, domestic funds sought returns overseas:
- Arbitrage Transactions: Borrowing yen at almost zero cost, converting it into dollars/euros to buy U.S. Treasury bonds, tech stocks, and assets in emerging markets, earning the interest rate differential (e.g., 0% on yen loans vs. 3% on U.S. bonds, resulting in a net profit of 3%). The scale of these transactions is estimated at $1-3 trillion, providing a source of "cheap capital" for global markets.
- Outflow of Institutions: Japanese pension funds (such as the GPIF) and insurance companies held significant overseas assets (e.g., U.S. Treasury bonds), making Japan the world's largest external creditor.
Why wasn't this a problem? Because most of the debt was held by domestic institutions (with the BOJ holding half of it), and the low interest rates, combined with capital outflows, suppressed domestic inflation, creating a balance of "high debt but low risk"—as long as Japanese interest rates remained lower than those abroad.
II. What Changed This Balance?
Inflation has returned! After 2020, the global pandemic disrupted supply chains and raised energy prices, helping Japan emerge from deflation:
- Inflation Exceeds Targets: Since 2022, prices in Japan have been rising, and wages have also started to increase (previously, it was thought wages would not rise), changing people's expectations.
- Central Bank Raising Interest Rates: The BOJ ended negative interest rates in 2024 and gradually raised them to 1% by June 2026 (the highest since 1995). The July meeting suggested further rate hikes due to ongoing inflation risks.
- Yen Depreciation: The yen fell below 164 against the dollar (a 40-year low), increasing import costs (e.g., making oil more expensive), forcing the government to intervene in the currency market multiple times (spending 11.7 trillion yen in April-May and an additional 8 trillion yen in July).
Japan and the U.S. are also cooperating quietly: The U.S. Treasury Secretary stated that the yen is "seriously undervalued," and the Federal Reserve has asked banks for quotes, as a sharp depreciation of the yen could affect U.S. exports (making Japanese goods cheaper) and disrupt global markets due to capital inflows.
III. Signals of Capital Flowing Back to Japan
Things have changed; domestic assets are now more attractive:
- Domestic Asset Returns: The yield on 30-year Japanese Treasury bonds has risen to around 4%, allowing pension funds and insurance companies to earn reasonable returns without bearing exchange rate risks (e.g., buying domestic bonds without converting into dollars, avoiding losses from yen appreciation).
- Adjustment of Institutional Portfolios: Japan's largest pension fund, the GPIF (with $1.8 trillion in assets), previously held 25% in domestic bonds and now holds 26.9%, with a gradual increase. Insurance companies are shifting from selling to buying domestic bonds, leading to capital inflows.
- Arbitrage Transactions Being Closed: Those who borrowed yen to buy overseas assets are now selling them as the yen appreciates (or expect it to appreciate), causing pressure on global markets. For example, in May 2026, Japan reduced its holdings of U.S. Treasury bonds by $67 billion.
IV. Impacts on Global Markets:
1. U.S. Treasury Bonds Under Pressure: Japan is the largest foreign holder of U.S. Treasury bonds ($1.14 trillion). If it continues to reduce its holdings, the U.S. will need to raise interest rates to attract more capital, increasing mortgage and corporate financing costs and making the economy more challenging.
2. Global Stock Market Volatility: When arbitrage transactions are closed, investors sell high-risk assets (e.g., tech stocks and emerging market equities). Historically, sharp rises in the yen have been accompanied by global stock market declines.
3. Chain Reaction in Asian Currencies: A significant depreciation of the yen could lead to similar depreciations in other Asian countries, affecting global trade due to reduced competitiveness.
4. Increased Coordination Between Japan and the U.S.: The U.S. is helping Japan with currency market interventions to prevent a sudden influx of capital that could impact its own economy, as it also relies on Japanese bond purchases.
V. Three Possible Futures:
1. Optimal Scenario: Wages and prices rise moderately, domestic yields attract capital, and the flow back is orderly. The BOJ gradually raises interest rates, while the Federal Reserve begins to lower theirs, narrowing the interest rate gap between Japan and the U.S., stabilizing the yen and minimizing global market volatility.
2. Base Case: Governments occasionally intervene in the currency market, institutions make minor adjustments to their portfolios, and capital flows back moderately. The yen fluctuates between 157-163, and U.S. Treasury bond yields rise slightly, keeping global markets under control.
3. Pessimistic Scenario: If interest rate hikes are too rapid or there are external shocks (e.g., rising energy prices, sudden Fed rate hikes), arbitrage transactions are liquidated on a large scale, causing global stock market crashes and soaring Japanese debt costs, leading to a confidence crisis.
The most critical question now is: Will the BOJ raise interest rates in September? Will the GPIF continue to increase its holdings of domestic assets? How effective will the yen intervention be? These factors will determine the pace of global capital flows.
In Conclusion
Japan is no longer the "free source of money" for the world. Its policy shift is reshaping global markets, and Japan's actions must be considered a significant indicator for future investments; it can no longer be treated as an exception.