Which 18th-century London trading bubble ended in the South Sea Crash of 1720?

The 18th-century London trading bubble that ended in the South Sea Crash of 1720 was the South Sea Bubble.

The South Sea Company received a government-backed monopoly over trade with Spanish South America in exchange for taking on part of Britain's national debt. Investors became excited about the company's supposed commercial prospects, even though its actual trading opportunities were far more limited than popular expectations suggested.

Its share price rose dramatically in 1720 as speculation spread. The company and other ventures attracted money from investors seeking quick profits. When confidence weakened, prices collapsed, ruining many investors and causing political scandal. Parliament investigated the company, and several directors and officials were accused of corruption.

The episode occurred alongside John Law's Mississippi Bubble in France, which is why the two are sometimes discussed together. They were separate companies and separate national episodes. The South Sea Bubble also predates modern stock exchanges and financial regulation, making it an important early example of speculative mania and a market crash.