Yen Returns to 159 Level as Intervention's Effectiveness Fades

The joint U.S.-Japan intervention's effectiveness is fading as the yen returns to the 159 level, testing policy limits. The currency's continued depreciation in recent weeks has erased about half of the gains from the July 31 intervention.

On August 12, the yen fell 0.1% to touch 159.39 before closing roughly flat. This comes after the joint U.S.-Japan intervention lifted the yen from around 163 to 155 on July 31, a historic move in which Washington and Tokyo jointly bought yen.

The interest rate gap between the U.S. and Japan remains a significant issue, with the 10-year U.S. Treasury yield standing at 4.686% compared to Japan's 2.846%. This spread provides investors with a powerful incentive to borrow low-yielding yen and rotate into higher-yielding dollar assets.

Jesper Koll, expert director at Monex Group, commented that intervention frightened the market but cannot stop the laws of finance from operating, capital always flows toward the highest returns. Masahiko Loo, FX strategist at State Street Global Advisors, noted that intervention has been effective in slowing speculation but has not yet worked in changing fundamentals.