The BOJ's Tapering Crossroads: How Policy Uncertainty Could Unleash Yen Vulnerabilities

Philip CarterMonday, Jun 9, 2025 6:16 pm ET
3min read

The Bank of Japan (BOJ) faces a pivotal decision at its June 16–17 policy meeting: whether to halt its bond tapering program amid weakening economic data and rising fiscal pressures. This choice carries profound implications for the yen, global bond markets, and capital flows. With the BOJ's balance sheet already swollen to ¥720 trillion—equivalent to 120% of Japan's GDP—any deviation from its gradual tapering path could amplify existing vulnerabilities, creating opportunities and risks for investors.

The Tapering Dilemma: Growth vs. Fiscal Sustainability

The BOJ's current bond tapering plan, initiated in April 2024, aims to reduce monthly purchases from ¥5.5 trillion to ¥3 trillion by March 2026. However, recent economic data underscores why this timeline may be in jeopardy.

Key Context:- Downward-Revised Forecasts: The BOJ slashed its 2025 GDP growth projection to 0.5% (from 1.0%) and trimmed 2025 core inflation to 2.2%, citing U.S. tariff risks and weak wage growth.- Super-Long Bond Yields: Yields on 30-year Japanese government bonds (JGBs) hit a record high of 1.7% in April 2025, signaling investor skepticism about the BOJ's ability to sustain its yield curve control (YCC) framework.- Fiscal Strain: Japan's debt-to-GDP ratio, the highest among major economies, could worsen if bond yields rise further. Even a 0.5% increase in yields could add ¥2.5 trillion to annual interest payments.

Ask Aime: What will happen to the yen if the BOJ stops tapering its bond purchases?

These pressures have sparked internal debates within the BOJ. Policy board members are split between maintaining the current tapering pace to normalize policy and pausing to stabilize bond markets. A pause would likely weaken the yen, as reduced BOJ bond purchases would decrease demand for JGBs, allowing yields to rise and the yen to depreciate.

Why the Yen Could Weaken Further

The yen has historically been sensitive to BOJ policy shifts. A halt in tapering would send a clear signal that the BOJ remains accommodative, diverging from global peers like the Federal Reserve. This divergence could amplify yen weakness, which has already been fueled by:

  1. Interest Rate Differentials: The U.S. 10-year Treasury yield (now at 4.0%) far exceeds Japan's 0.5%, widening the incentive for carry trades.
  2. Yield Curve Control Stress: The BOJ's YCC target of 0.5% on 10-year bonds is under strain. A tapering pause would reduce JGB supply, but rising inflation expectations could still push yields higher.
  3. Global Capital Flows: A weaker yen could redirect capital toward higher-yielding emerging markets or U.S. equities, exacerbating Japan's trade deficit.

Historical Parallels: In 2020, the BOJ's emergency asset purchases during the pandemic sent the yen to a 5-year low against the dollar. A similar response to current pressures could see USD/JPY breach 150 by year-end, up from its current 144.

Strategic Positioning: Short JPY or Long USD/JPY?

Investors should consider the following strategies to capitalize on yen weakness and BOJ policy uncertainty:

Ask Aime: Why the Yen Could Weaken Further

  1. Short Yen Exposure:
  2. Instrument: Sell JPY/USD futures or options contracts. A 5% depreciation from current levels would yield significant gains.

  3. Risk: Geopolitical events (e.g., U.S.-Japan trade agreements) or a sudden BOJ rate hike could reverse the trend.

  4. Long USD/JPY Carry Trades:

  5. Strategy: Borrow yen at near-zero rates, convert to USD, and invest in higher-yielding assets like U.S. Treasuries or equities.

  6. Caution: Carry trades are vulnerable to yen rallies, which can occur during global risk-off episodes.

  7. Avoid Long-Duration JGBs:

  8. Rising yields and fiscal risks make super-long bonds (e.g., 30-year JGBs) particularly dangerous. Short-term notes may offer better stability.

Risks and Contingencies

  • Policy Surprise: If the BOJ accelerates tapering to curb bond market volatility, yields could decline temporarily, stabilizing the yen. Monitor the BOJ's Summary of Opinions (June 25) for internal dissent signals.
  • Inflation Surprise: A sustained rise in core inflation above 2.5% could force the BOJ to hike rates, altering the yen's trajectory.
  • Global Shocks: A U.S. recession or China's economic slowdown could reduce demand for Japanese exports, compounding yen weakness.

Conclusion: Prepare for a Policy Pivot

The BOJ's June decision is a critical juncture. With growth faltering and fiscal risks mounting, a pause in tapering is increasingly likely. This would weaken the yen, reshape global yield curves, and redirect capital flows. Investors should position defensively, prioritizing short JPY exposure while hedging against sudden policy shifts. As the saying goes: In uncertainty, liquidity and agility reign. The BOJ's next move will test both.

Final Note: Monitor the BOJ's June 17 policy statement and the subsequent Outlook Report for clues on tapering plans. A delay beyond the current ¥3 trillion target by March 2026 would confirm the yen's bearish trajectory.