Which 18th-century speculative bubble collapsed in the 1720 stock-market crash in Britain?

The South Sea Bubble was the 18th-century speculative bubble that collapsed in Britain during the 1720 stock-market crash.

The South Sea Company received a government-backed plan to convert and manage portions of British government debt. Investors became excited about the company’s supposed commercial opportunities, especially its claimed access to trade with Spanish America. Share prices rose dramatically as speculation spread beyond the company itself.

Prices collapsed later in 1720, ruining many investors and causing political scandal. The episode is often discussed alongside John Law’s Mississippi Bubble in France, which also burst in 1720. A key distinction is that South Sea shares were not simply a modern corporation’s ordinary growth story: government debt conversion, political influence, limited information, and speculative enthusiasm all helped create the bubble.