The South Sea Company became famous for the speculative collapse called the South Sea Bubble in 1720.
Founded in 1711, the company received a British government monopoly over trade with Spanish South America, although its realistic commercial opportunities were much more limited than promoters suggested. It also took on part of the British national debt, and its shares rose dramatically as investors were encouraged to believe that vast profits were possible.
The boom attracted members of the public and prominent figures, while Parliament passed legislation intended to restrict competing joint-stock ventures. When confidence weakened later in 1720, the share price collapsed, ruining many investors and causing a political scandal.
The South Sea Bubble is often discussed alongside France's Mississippi Bubble, which burst during the same period. They were separate schemes, however: the South Sea Company was British, while the Mississippi Company was associated with John Law's financial system in France.