The South Sea Company’s collapse symbolized the 1720 English stock-market crash known as the South Sea Bubble.
The company received a government-backed monopoly over trade with parts of Spanish America, although its real commercial prospects were far more limited than many investors believed. It promoted its shares aggressively and arranged to convert government debt into company stock, drawing in aristocrats, merchants, and ordinary savers.
Share prices rose dramatically during the first half of 1720. Parliament also passed the Bubble Act, which restricted unauthorized joint-stock companies and helped channel speculative money toward favored ventures. When confidence weakened, investors rushed to sell, and the share price collapsed.
The South Sea Bubble is often confused with the Mississippi Bubble, a separate French crisis associated with John Law. Both were major 1720 speculative collapses, but the South Sea Company was the central English example. The episode helped inspire later debates about financial regulation and investor protection.