What was the name of the 1720 British speculative collapse centered on the South Sea Company?

The 1720 British speculative collapse centered on the South Sea Company was the South Sea Bubble.

The South Sea Company received a government-backed monopoly over trade with Spanish South America, although its real commercial prospects were far more limited than many investors imagined. The company’s shares rose dramatically as it promoted ambitious expectations and attracted speculation.

Investors bought shares partly through credit, and the rising price encouraged more buying. When confidence weakened later in 1720, the price collapsed, ruining many investors and damaging trust in joint-stock companies.

The episode occurred alongside John Law’s Mississippi Bubble in France, but they were separate schemes. Parliament responded with the Bubble Act of 1720, which restricted the creation of companies without a royal charter or parliamentary authorization. Isaac Newton was among those who lost money, famously saying he could calculate the motions of heavenly bodies but not the madness of people.