Bob Elliott
· Nonconsensus
· May 05, 2026 at 10:06
· ⏱ 5 min read
| Read on Substack ↗
Summary
Central bank interventions in major floating FX markets, including the Plaza Accord and recent Japanese efforts, have only short-term effects on exchange rates. The long-term trajectory of currencies is determined by fundamental pressures such as interest rate differentials and monetary policy, not by intervention size alone.
•Japan spent over $200 billion in intervention efforts in 2022 and 2024, totaling about 15% of its reserves, yet the yen still pushed through 160 per dollar.
•The Plaza Accord (1985) deployed only about $10 billion over six weeks, representing just 0.2% of US GDP, yet the dollar fell ~4% on announcement and 50% over two years.
•The dollar's decline after the Plaza Accord was driven by the Fed cutting rates 400 bps in late 1984/early 1985, which compressed US-German rate differentials from >500 bps to near zero.
•US real short rates were running at nearly 7.5% in 1984; as the Fed eased and real rates fell to normal levels, the dollar weakened significantly.
•The article argues that in large liquid developed FX markets, policymakers cannot change currency trajectories without a meaningful shift in underlying fundamental drivers.