What was the nickname of the 1720 English financial crash involving the South Sea Company?

The 1720 English financial crash involving the South Sea Company was called the South Sea Bubble.

The South Sea Company was granted a monopoly over British trade with Spanish South America, although its realistic trading opportunities were limited. The company proposed converting government debt into shares, and its stock price rose dramatically in 1720 as investors expected enormous profits and responded to aggressive promotion.

The boom attracted money into the company and into many other speculative ventures. Parliament passed the Bubble Act in 1720, restricting companies that operated without a royal charter or parliamentary authority, but the measure did not prevent the South Sea share price from collapsing. Numerous investors suffered severe losses, and public anger followed.

The event is often grouped with John Law’s Mississippi Bubble in France, which collapsed in the same broad period, but they were separate schemes. “Bubble” describes the pattern of speculative price inflation followed by a collapse. The South Sea episode became one of Britain’s best-known early examples of a stock-market bubble.