In September 1985, finance ministers from the United States, Japan, West Germany, France, and the United Kingdom gathered at the Plaza Hotel in New York and did something remarkable: they admitted, publicly and in concert, that the dollar was too strong and needed to come down. Within two years, the greenback had lost roughly half its value against the yen and the deutsche mark. It remains the most successful coordinated currency intervention in modern history — and almost certainly the last of its kind.

The Plaza Accord matters not because it can be repeated, but because it illuminates what made such cooperation possible and why the conditions that enabled it have largely vanished. Understanding the Plaza is understanding the architecture of the global monetary system, its load-bearing walls and its cracks.

The problem the Plaza solved

By the mid-1980s, the Reagan administration's combination of tax cuts and military spending had produced enormous budget deficits. The Federal Reserve, under Paul Volcker, had crushed inflation with punishingly high interest rates. The result was a dollar that had appreciated by roughly 50 percent against major currencies since 1980. American manufacturers were being priced out of global markets, and protectionist sentiment in Congress was reaching a boil.

The genius of the Plaza Accord was recognizing that everyone's interests temporarily aligned. Japan and Germany wanted to avoid American tariffs. The United States wanted a cheaper dollar without abandoning its fiscal stance. All parties preferred orderly depreciation to a disorderly crash. The deal worked because it formalized what markets already suspected: the dollar was overvalued and policymakers would no longer defend it.

Why it cannot happen again

The Plaza succeeded because of a specific geopolitical configuration. The participating nations were military allies with deep institutional ties. Their central banks were credible and their finance ministries spoke with authority. Most importantly, capital markets were far smaller relative to government resources. When the G5 announced their intentions, traders believed they had the firepower to follow through.

Today, daily foreign exchange turnover exceeds several trillion dollars — dwarfing any conceivable intervention fund. China, now the world's second-largest economy, was not at the table in 1985 and would be essential to any equivalent agreement today. The geopolitical trust required for such coordination has frayed considerably. Nations still intervene in currency markets, but they do so unilaterally and often covertly, hoping to smooth volatility rather than engineer fundamental realignments.

The unintended consequences

The Plaza's success came with a price, particularly for Japan. The rapid yen appreciation contributed to an asset bubble of historic proportions. Japanese policymakers, fearing the strong yen would crush exports, kept monetary policy loose for too long. By the end of the decade, Tokyo real estate was nominally worth more than all the land in the United States. The subsequent crash inaugurated what the Japanese call the Lost Decades.

This is the Plaza's uncomfortable lesson: even successful interventions have second-order effects that can take years to manifest. The ministers at the Plaza Hotel solved their immediate problem elegantly. They also set in motion forces that would reshape the Japanese economy for a generation.

Our take

The Plaza Accord is often invoked by those who believe governments can simply will exchange rates into submission. The reality is more humbling. The deal worked because of unrepeatable circumstances: aligned incentives among allies, manageable capital flows, and credible institutions. It also worked because markets were already leaning in the same direction. The Plaza did not defy market forces; it channeled them. Those hoping for a new Plaza — whether to address trade imbalances with China or to manage dollar strength — should study not just the agreement's success, but the wreckage it left in Tokyo. Coordination is powerful. It is also rare, fragile, and never free.