Which 1720 British share-price collapse is called the South Sea Bubble?

The 1720 British share-price collapse is called the South Sea Bubble.

The South Sea Company received a government-backed monopoly over trade with parts of South America, although its realistic trading prospects were far less impressive than many investors believed. The company promoted expectations of enormous profits, and its shares rose sharply during 1720.

Investors from different social classes bought shares as speculation spread. Parliament passed the Bubble Act in June 1720, restricting some competing joint-stock companies, but the measure did not prevent the South Sea Company’s price from rising. Later in the year, confidence broke and the shares plunged.

The episode is often grouped with the contemporaneous Mississippi Bubble in France. It is also sometimes confused with the much earlier Dutch tulip speculation, but the South Sea Bubble involved company shares and government finance rather than tulip bulbs.