The British government suddenly deregulates financial markets, leading to a total restructuring of the way in which they operate in the country, in an event now referred to as the Big Bang.

The phrase Big Bang, used in reference to the sudden deregulation of financial markets, was coined to describe measures, including abolition of fixed commission charges and of the distinction between stockjobbers and stockbrokers on the London Stock Exchange and change from open outcry to screen-based electronic trading, effected by UK Prime Minister Margaret Thatcher in 1986.