Which 1720 British bubble collapsed after speculation in a company trading with South America?

The 1720 British bubble that collapsed around a South American trading company was the South Sea Bubble.

The South Sea Company received rights connected with British trade to Spanish South America and later proposed converting government debt into company shares. Promotion, political support, and easy speculation drove its share price to extraordinary levels in 1720.

The price collapsed later that year, ruining many investors and causing a political scandal in Britain. Parliamentary investigations revealed corruption and improper dealings involving company promoters and public officials.

The South Sea Bubble is often discussed alongside France's Mississippi Bubble, another major speculative episode of 1720. 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.