What it means
By the mid-1980s the dollar had soared, rising roughly 50% against major currencies in five years. American exporters were being crushed, and protectionist pressure in Congress was building fast.
On September 22, 1985, finance ministers and central bankers of the G5 met at the Plaza Hotel in New York and agreed the dollar was too strong. They committed to coordinated selling of dollars to push its value down.
The intervention worked, dramatically. Over the following two years the dollar fell steeply, by some measures around 40% against the yen and the mark, easing the strain on US manufacturing.
The speed of the decline created its own anxiety, so in 1987 the same countries signed the Louvre Accord to stabilise the dollar and stop the slide. Managed exchange rates had become an accepted tool of statecraft.
The Federal Reserve's own historical discussions of central bank coordination cite the Plaza Accord as the landmark example of joint intervention, a case where diplomacy moved currency markets as much as economics did. The Accord's side effects echo to this day.
Many economists link the yen's rapid rise to Japan's easy-money response, which inflated the late-1980s asset bubble whose collapse began Japan's lost decades. It also demonstrated both the power and the limits of coordination: governments can bend exchange rates when they act together, but they cannot fully control where the adjustment ends.
For a non-finance reader, the Plaza Accord is proof that exchange rates are not purely natural phenomena. When the biggest economies decide a currency must move, and put their reserves behind the decision, it moves.
For currency traders, the Accord remains the reference case for intervention. Every time a finance minister hints that a currency has moved too far, markets ask whether another Plaza-style coordinated push is forming.
In practice
Real-world examples.
Example
A US tractor manufacturer regains European customers in 1986 and 1987 as the coordinated dollar decline makes its prices competitive again. The episode is still taught as the clearest modern proof that exchange rates respond to policy, not just to trade flows.
Example
Japan's central bank eases policy to cushion the yen's Plaza-driven surge, feeding liquidity that later inflates the stock and property bubble of the late 1980s.
Example
Two years after the Plaza meeting, the same nations sign the Louvre Accord to halt the dollar's fall, showing that even successful interventions need an exit plan.
Formula
Calculation
There is no single formula for the intervention itself, which was coordinated selling of dollars and buying of yen and marks. The effect on a currency can be measured as percentage change = (new rate - old rate) / old rate x 100.
Worked example using illustrative round rates, not exact historical quotes. Suppose the exchange rate falls from 240 yen per dollar to 150 yen per dollar.
- Percentage change in the dollar = (150 - 240) / 240 x 100 = -37.5%.
- A $100,000 American machine costs a Japanese buyer 240 x $100,000 = 24,000,000 yen before the fall and 150 x $100,000 = 15,000,000 yen after it, which is 37.5% cheaper.
- Seen from the other side, one yen buys 1/240 = $0.004167 before and 1/150 = $0.006667 after, so the yen has risen by 60%.
- That is why a fall of 37.5% in one currency is a rise of 60% in the other.Case study
Seen in the real world.
This case study is fictional and illustrative. Marchetti Tools, a made-up Ohio machine-tool maker, had lost a third of its export orders by 1984 because European buyers found American goods impossibly expensive at the prevailing exchange rate. Its owner watched the Plaza Accord announcement in September 1985 with cautious hope. Over the next two years, as the dollar slid, German and Japanese customers returned, and by 1987 exports had recovered enough for the firm to rehire twenty machinists.
The same shift squeezed its Japanese competitor, whose government pushed interest rates down to soften the yen's rise. Marchetti's owner retired telling anyone who would listen that a single hotel meeting in New York had saved his company. His story is simplified, but thousands of American factory towns lived some version of it.
Watch out
Common mistakes.
- Thinking the Plaza Accord targeted the yen alone; it was a multilateral G5 commitment to realign the dollar against all major currencies.
- Believing intervention worked by itself; the Accord succeeded because policy signals, actual reserve sales, and an already-turning market reinforced each other.
- Forgetting the aftermath, since the Louvre Accord of 1987 was needed to stop the decline the Plaza had started, and Japan's response fed its bubble. Currency coordination without domestic policy follow-through tends to produce overshoots like the ones that followed.
Questions
People also ask.
What did the Plaza Accord do?
It committed the G5 nations to coordinated intervention to depreciate the overvalued US dollar, which fell sharply over the following two years. It remains the most cited example of successful coordinated currency intervention.
Why was it called the Plaza Accord?
It was signed at the Plaza Hotel in New York City on September 22, 1985.
Did the Plaza Accord cause Japan's bubble?
Many economists argue it contributed, because Japan loosened monetary policy to offset the yen's rise, inflating asset prices that collapsed from 1990.
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