Which 1720 financial bubble is often regarded as Britain's first major stock-market crash?

The South Sea Bubble is often regarded as Britain's first major stock-market crash.

The South Sea Company received a government monopoly over trade with Spanish South America, although its actual commercial prospects were far more limited than public enthusiasm suggested. In 1720, its shares rose dramatically as investors expected wealth from trade and a plan to convert government debt into company stock.

Prominent investors and members of the political establishment became involved, while speculative companies multiplied. When confidence weakened later in 1720, the South Sea Company's shares collapsed, ruining many investors and causing a major political scandal.

The South Sea Bubble occurred alongside France's Mississippi Bubble, but the two were separate schemes. Parliament investigated the South Sea Company, and the scandal damaged trust in company promotion and government finance. The episode is an early example of how persuasive narratives, easy credit, and crowd speculation can inflate asset prices far beyond underlying business prospects.