What was the name of the 1720 British market bubble whose collapse ruined many investors?

The 1720 British market bubble whose collapse ruined many investors was the South Sea Bubble.

The South Sea Company received a government-backed monopoly over trade with parts of South America and persuaded investors that its commercial prospects were enormous. Its shares rose dramatically in 1720, despite the company’s limited ability to deliver the promised profits. Speculation spread through London, and many people borrowed money or joined newly formed ventures.

When confidence weakened, the share price collapsed. The losses damaged investors, caused political scandal, and led Parliament to investigate the company’s directors. The episode became one of the classic early examples of a speculative bubble linked to misleading expectations and easy credit.

The Mississippi Bubble occurred in France around the same period, under John Law. Tulip Mania was a much earlier Dutch speculation involving tulip bulbs, so neither is the British event named here.