The South Sea Bubble reached its peak and collapsed in 1720.
The South Sea Company was founded in 1711 and received a monopoly over British trade with parts of Spanish America. In practice, that commercial opportunity was far more limited than many investors believed. The company also took on government debt, helping it gain political influence and public attention.
Shares rose dramatically during 1720 as investors speculated on future profits. The boom drew in wealthy individuals, ordinary savers, and many copycat companies. When confidence weakened later that year, prices fell rapidly and the bubble burst.
The South Sea Bubble is often discussed alongside France's Mississippi Bubble, which also collapsed in 1720. The scandal damaged public confidence in company promotion and led Parliament to pass the Bubble Act in 1720, although that law did not permanently prevent speculative manias.