Black Wednesday, in politics and economics, was on September 16, 1992, when the British Conservative government was forced to withdraw the pound sterling from the European Mechanism of Change (ERM) after it was unable to hold on to above the agreed lower limit. George Soros, the foremost investor in the forex market, earned more than a billion pounds in earnings from the short sale of sterling.

In 1997, His Majesty's Treasury analyzed and estimated the cost of Black Wednesday at 3,400 million pounds, and in 2005, thanks to the Freedom of Information Act of 2000, it became known that the Actual cost could have been about 3300 million pounds.

Commercial losses in August and September of 1992 were estimated at 800 million pounds, but the main loss for taxpayers arose because the devaluation could have given them profits. The documents show that if the government had maintained 24 billion dollars in reserves of foreign currency and the pound had fallen in the same amount, the United Kingdom would have obtained a profit of 2400 million pounds due to the devaluation of the pound.

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