John Blunt promoted the South Sea Company before its share-price collapse in the South Sea Bubble of 1720.
Blunt was a director of the South Sea Company and a key architect of the scheme that exchanged government debt for company shares. The company promised investors access to lucrative trade with Spanish America, although its practical trading opportunities were far more limited than the publicity suggested. Share prices rose dramatically as speculation spread.
The bubble burst in 1720 when confidence weakened and investors rushed to sell. The collapse ruined many speculators and caused a political scandal in Britain. Parliamentary investigations found corruption and improper dealings among company directors and public officials.
Isaac Newton is often mentioned in accounts of the bubble because he invested and reportedly lost heavily, but he did not promote the company. Robert Walpole later helped manage the political crisis and is not the financier sought here. The South Sea Bubble became an enduring example of speculative excess and misleading commercial optimism.