In the late spring of 1720, Sir Isaac Newton decided to sell his stocks.

Newton had been an investor in the South Sea Company, a famous enterprise which effectively commanded a trading monopoly with South America.

The investment had already made Newton a lot of money, he was up more than 100% in a very short time.

In fact, investors were clamoring to buy up the South Sea Company’s stock, and the share price kept climbing. And climbing.

Newton sensed that the market was getting overheated. It no longer made sense to him. So he sold.

There was only one problem: the share price of the South Sea Company kept climbing.

All of Newton’s friends were getting rich. So, against his better judgement, Newton went back in, repurchasing shares at more than three times the price of his original stake.