Cartoon depiction of the South Sea bubble. Investors, including the government, bought shares in the rising stock of the South Sea Company, creating an unsustainable investment 'bubble'. The bubble finally broke in 1720, when the price of the South Sea Company's stock collapsed, bankrupting many private investors and destabilising government finances. It was one of the greatest financial shocks of the 18th century and led to tighter regulation and investment in government bonds as a means to fund the national debt.