What was the 1720 speculative collapse involving the South Sea Company called?

The 1720 speculative collapse involving the South Sea Company was called the South Sea Bubble.

The South Sea Company received a government-backed monopoly over trade with parts of Spanish America, although its actual trading activity was much smaller than many investors imagined. Its shares rose dramatically as the company promoted ambitious expectations and investors rushed to participate.

The price reached about £1,000 in August 1720 before collapsing later that year. Many investors borrowed to buy shares, and the reversal caused severe financial losses in Britain. Parliament investigated the company’s directors and the conduct of several officials.

The South Sea Bubble occurred alongside the Mississippi Bubble in France, a separate crisis associated with John Law’s financial system. The phrase “bubble” became a lasting metaphor for speculative markets whose prices are driven far beyond underlying business prospects.