The South Sea Company was at the center of the South Sea Bubble, one of the most famous stock-market crashes of 1720.
Founded in 1711, the company received a monopoly over British trade with parts of Spanish-controlled South America in exchange for taking on government debt. In practice, its commercial opportunities were far more limited than many investors imagined. Promotional claims, political connections, and expectations of enormous overseas profits nevertheless helped drive its share price sharply higher.
Parliament later approved a plan that gave the company a larger role in converting government debt into shares. Investors rushed in, and the price rose to extraordinary levels before confidence collapsed. By the end of 1720, the shares had fallen dramatically, ruining many investors and provoking political scandal.
The South Sea Bubble is often mentioned alongside the Mississippi Bubble in France, which collapsed during the same year. They were separate schemes, although both demonstrated how easy credit, persuasive promotion, and speculative expectations could inflate asset prices beyond realistic business prospects.