What was the name of the 1720 English stock-market collapse involving the South Sea Company?

The 1720 English stock-market collapse involving the South Sea Company was called the South Sea Bubble.

The South Sea Company received a government-backed monopoly over trade with Spanish South America and promoted ambitious expectations about its future profits. Its shares rose dramatically in 1720 as investors bought into increasingly speculative promises. The company also helped convert portions of government debt into shares.

When confidence weakened, the share price collapsed, ruining many investors and causing a political scandal in Britain. Parliament investigated the company’s directors and the officials who had supported or benefited from the scheme. The crisis also led to the Bubble Act of 1720, which restricted unauthorized joint-stock companies.

The South Sea Bubble occurred alongside John Law’s Mississippi Company bubble in France. Those events are related examples of early modern financial speculation, but they were separate companies and national crises. The English episode is therefore not the Mississippi Bubble, even though both occurred during the same remarkable year.