European Exchange Rate Mechanism
Soros had been building a huge short position in pounds sterling for months leading up to September 1992. Soros had recognized the unfavorable position of the United Kingdom in the European Exchange Rate Mechanism. For Soros, the rate at which the United Kingdom was brought into the European Exchange Rate Mechanism was too high, their inflation was also much too high (triple the German rate), and British interest rates were hurting their asset prices.