The Yen Suffers Its Worst Plunge in Four Decades

The yen hit 163.23 to the dollar on July 21, 2026, its lowest level since December 1986. This historic drop exposes the limits of a currency weakened by negative real rates and revives the narrative of bitcoin as a scarce asset.

In brief

• The yen fell to 163.23 to the dollar on July 21, 2026, a level not seen in nearly 40 years.
• The rise in oil, U.S. yields, and the weakness of Japanese real rates have increased the pressure.
• The limited supply of Bitcoin feeds its monetary narrative, without eliminating its price risk.

The yen crosses 163, a threshold forgotten for four decades

The 160 threshold had already put Tokyo on alert. One month after the Bank of Japan raised its rates to their highest level since 1995, the yen nevertheless resumed its fall and broke 163 to the dollar. The move confirms that Japanese monetary tightening is not enough at this stage to close the gap with U.S. yields.

According to Reuters, the Japanese currency reached 163.24 during trading in New York on July 21, its weakest level since the end of 1986. On the same day, the yield on the 10-year U.S. Treasury bond touched 4.64%, while the 30-year yield climbed to 5.15%. These levels supported the dollar.

Oil added further pressure. Brent hit $92.67 a barrel in Asia on July 22, against the backdrop of escalation between the United States and Iran. Japan imports most of its energy. More expensive oil increases its external bill and weakens the yen, while the dollar also benefits from its safe-haven status.

Tokyo threatens to intervene, but the market watches the rates

The Japanese government can buy yen to curb a disorderly decline. However, traders doubt the lasting effect of any intervention if the yield gap with the United States remains so wide.

Tokyo already conducted record yen purchases in April and May 2026, when the dollar exceeded 160 yen. Their effect faded. Japanese Finance Minister Satsuki Katayama again promised “decisive” action in case of excessive moves, without announcing an official threshold.

Japanese real rates remain negative because inflation still exceeds the available monetary yield. HSBC thus estimates that the dollar-yen pair could mainly trade between 160 and 165, with occasional interventions to limit excesses.

The Bank of Japan still has room to maneuver. A Reuters survey published on July 23 indicates that 86% of economists surveyed anticipate another rate hike in 2026, possibly as early as October. Conversely, 95% of them believe the central bank will not move during the current quarter.

Bitcoin gains an argument, not a risk-free status

The yen’s fall strengthens the scarce assets argument: a central bank cannot increase Bitcoin’s maximum supply, which its protocol caps at 21 million units. A saver exposed only to cash thus suffers a loss of purchasing power of their currency when prices rise or the exchange rate declines.

This comparison has its limits, however. The yen serves as a unit of account, a means of payment, and a store of savings in an economy worth several thousand billion dollars. Bitcoin remains a volatile global asset whose price depends on liquidity, regulation, and risk appetite.

The market reminded us on July 23. While the yen was still trading near its 40-year low, Bitcoin gave up 0.5% to $65,557.35, according to Reuters. Programmed scarcity can support a long-term thesis, but it neither guarantees an immediate rise nor constant protection against every monetary shock.

In summary, the yen concentrates three tensions: negative real rates, a heavier energy bill, and doubts about public finances. The Bank of Japan’s next decisions, a possible Tokyo intervention, and the sensitivity of Bitcoin to Brent will determine what happens next. This analysis is not financial advice: scarcity does not eliminate volatility.