There are some important lessons for investors in all this. First, when considering any trade, it’s important to assess the risk/reward ratio – the investment’s potential upside relative to the danger of failure. The more favorable this ratio, the more money you can reasonably invest. While his partner came up with the original idea of shorting the pound, Soros made the key decision to increase the position over 500%. He realized that either the pound would stay relatively stable – in which case Quantum would only lose a little money – or else the British government would abandon the ERM, in which case the bet would pay off big. It was thus a relatively low-risk, high-opportunity trade which Soros sized accordingly 🤙

Another important takeaway is the existence of feedback loops in which investors' perceptions affect economic fundamentals – which in turn affect investor perceptions. In this case, investors saw the pound as overvalued and started shorting it. That caused a shift in economic fundamentals, with the British government raising interest rates in order to prop up the currency. That led investors to conclude that the British government was becoming desperate, and that its attempts to defend the pound were unsustainable. This idea of feedback loops is called “reflexivity” – and its application to financial markets was actually pioneered by Soros himself.