Bubble Act 1720 (also Royal Exchange and London Assurance Corporation Act 1719) was an Act of the Parliament of Great Britain passed on 11 June 1720 that incorporated the Royal Exchange and London Assurance Corporation, but more significantly forbade the formation of any other joint-stock companies unless approved by royal charter. Its provisions were extended later by the Bubble Schemes, Colonies, Act 1740 to include its colonies, particularly Massachusetts.
Various motivations have been suggested for the Act. They include the desire to prevent the speculation that produced the contemporary South Sea Bubble, an attempt to prevent smaller non-charter companies from forming and so reduce the importance of Parliament in regulating businesses; or the South Sea Company itself wanting to prevent other bubbles from forming that might have decreased the intensity of its own.
Recent scholarship indicates that the last was the cause: it was passed to prevent other companies from competing with the South Sea Company for investors' capital.
In fact, the Act was passed in June 1720, before the peak of the bubble. The Act was repealed in 1825.
The most significant provision read:
All undertakings ... presuming to act as a corporate body ... raising ... transferrable stock ... transferring ... shares in such stock ..., either by Act of Parliament or any charter from the Crown, ... and acting under any charter ... for raising a capital stock ... not intended ... by such charter ... and all acting ... under any obsolete charter ... for ever be deemed illegal and void.