The Broken Pound on Black Wednesday

George Soros, the Impossible Trinity, and the Ten-Billion-Dollar Wager Against the Bank of England

Late in the afternoon of Tuesday, September 15, 1992, inside the Manhattan offices of the Quantum Fund on Seventh Avenue, chief portfolio manager Stanley Druckenmiller walked into George Soros's office to lay out a currency trade. Britain had joined the European Exchange Rate Mechanism (ERM) two years earlier at a central peg of 2.95 Deutsche Marks to the pound. That afternoon, German Bundesbank president Helmut Schlesinger had hinted to reporters that European currencies needed a broader realignment. Druckenmiller explained why the British pound could not hold its floor and proposed building a $1.5 billion short position. Soros listened to the asymmetric math of the trade and frowned at the modest size, asking why they were stopping at two billion dollars if the thesis was sound and urging Druckenmiller to go for the jugular.

Overnight between September 15 and the London open on Wednesday, September 16, 1992, Quantum Fund traders borrowed and sold more than $10 billion worth of British pounds for Deutsche Marks. What made the trade nearly risk-free for Soros was a structural contradiction in international macroeconomics known as the Mundell-Fleming Impossible Trinity. A sovereign nation can choose at most two of three policy goals simultaneously: free cross-border capital flows, a fixed exchange rate, and an independent domestic interest-rate policy tailored to its own business cycle.

In the autumn of 1992, Germany and Britain sat at opposite ends of the economic cycle. Following the reunification of East and West Germany in 1990, Bonn spent heavily on eastern reconstruction. That spending stoked inflation and prompted the Bundesbank to raise German interest rates to 8.75 percent. Britain, by contrast, was mired in a deep housing and manufacturing recession. Unemployment had climbed past 2.8 million, and ninety percent of British homeowners held floating-rate mortgages tied directly to the Bank of England's base rate.

To keep the pound inside its narrow ERM band above 2.778 Deutsche Marks while capital flowed freely across Europe, Britain had only two tools. It could buy pounds on the open market using finite foreign-exchange reserves, or it could match and exceed German interest rates. Both tools contained an obvious breaking point. If the Bank of England defended the peg at 2.778, Soros and Druckenmiller knew the pound would never be revalued upward during a British recession. Their upside risk on a short position was capped near zero, whereas a devaluation promised an instant ten-to-fifteen-percent windfall.

When London markets opened at 7:30 a.m. on Black Wednesday, September 16, Bank of England dealers at Threadneedle Street faced a wall of sterling sell orders from Quantum, pension funds, and corporate treasurers. By 9:00 a.m., the Bank was buying two billion pounds an hour just to hold the 2.778 floor. At 10:30 a.m., Prime Minister John Major and Chancellor of the Exchequer Norman Lamont authorized an emergency interest-rate hike from 10 percent to 12 percent. Currency traders barely blinked. Everyone knew that a twelve-percent mortgage rate would bankrupt British households and deepen the slump. At 2:15 p.m., a desperate Lamont announced a second rate hike to 15 percent effective the next morning. Selling accelerated immediately because every desk on the street realized the political bluff had failed. At 7:40 p.m., Lamont stepped outside 11 Downing Street to announce Britain's suspension from the ERM, netting Soros's fund over $1 billion in profit. While the Bank of England burned through twenty-seven billion dollars of reserves and hiked interest rates to fifteen percent in a single morning, Britain's exit from the peg lowered borrowing costs and launched sixteen consecutive years of economic expansion.