What was the name of the 1720 English speculative bubble centered on the South Sea Company?

The 1720 English speculative bubble centered on the South Sea Company was the South Sea Bubble.

The South Sea Company received government support to assume part of Britain’s national debt in exchange for shares and commercial privileges. Expectations of enormous profits from trade with Spanish America helped push its share price dramatically higher in 1720. The company’s actual trading prospects were far more limited than the promotional excitement suggested.

Investors from many social classes bought shares, often encouraged by rising prices and easy credit. The boom also created a wave of unofficial ventures, remembered as “bubble companies,” some of which offered implausible projects. When confidence turned, South Sea shares collapsed, ruining many investors and causing a political scandal.

The South Sea Bubble was part of a wider European speculative episode that also included France’s Mississippi Bubble. Britain responded with the Bubble Act of 1720, which restricted joint-stock companies operating without a charter or parliamentary authorization. The act is sometimes described as a direct ban on speculation, but its legal target was unauthorized corporate activity rather than every form of share trading.