Why the yen matters

The Japanese yen’s recent weakness triggered an unprecedented joint currency intervention by the US and Japan, marking a rare shift in global financial policy. While the move aimed to stabilize the yen, the primary driver appears to be the protection of the US Treasury market. Japan, as a major holder of US government bonds, faces pressure to raise interest rates or sell Treasuries to support its currency, both of which would drive up US borrowing costs. By utilizing the Foreign and International Monetary Authority (FIMA) repo facility, the US provided a temporary liquidity backstop to prevent Japan from dumping Treasuries. This intervention highlights the US government's sensitivity to rising bond yields and its reliance on foreign demand to sustain a significant fiscal deficit, revealing that the operation was less about the yen and more about securing US financial stability.