In order to be able to focus on academic research and avoid financial worries, economist Keynes once went out to give lectures to earn tuition fees, but the income from tuition fees was limited after all. So in August 1919, he borrowed several thousand pounds to engage in speculation in forward foreign exchange.

In just 4 months, Keynes made a net profit of more than 10,000 pounds, which is equivalent to his income from lecturing for 10 years. But three months later, Keynes lost all the profits and borrowed principal. Seven months later, Keynes got involved in cotton futures trading and achieved great success again.

Keynes developed almost all futures products, and also dabbled in stocks. By the time he "washed his hands in a golden basin" due to illness in 1937, he had accumulated a huge amount of wealth that he would never be able to enjoy in his lifetime.

Unlike ordinary gamblers, as an economist, Keynes, in addition to earning considerable profits in this speculative business, the biggest and most beneficial gain was the discovery of the "idiot theory". Some people also call it the "Bo Fool Theory".