Which 18th-century British company stood at the center of the 1720 stock-market crash?

The South Sea Company stood at the center of Britain’s 1720 stock-market crash.

The South Sea Company received government support and promoted expectations that its trade with Spanish America would become enormously profitable. Its shares rose dramatically during 1720, attracting aristocrats, merchants, and ordinary investors into a speculative boom.

When confidence weakened, the share price collapsed. The episode became known as the South Sea Bubble, one of the most famous early stock-market bubbles. Parliament investigated the company’s conduct, and several politicians and financiers faced severe reputational or financial consequences.

A related bubble occurred in France around the Mississippi Company, led by John Law. The two episodes are often discussed together because both involved state-backed companies, aggressive promotion, and unrealistic expectations. They were not one single company or one identical market. The South Sea crash also encouraged later restrictions on joint-stock promotion in Britain.