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.

London Stock Exchange (LSE) is a stock exchange in the City of London, England, United Kingdom. As of August 2023, the total market value of all companies trading on the LSE stood at $3.18 trillion. Its current premises are situated in Paternoster Square close to St Paul's Cathedral in the City of London. Since 2007, it has been part of the London Stock Exchange Group. The LSE is the most-valued stock exchange in Europe as of 2023. According to the 2020 Office for National Statistics report, approximately 12% of UK-resident individuals reported having investments in stocks and shares. According to the 2020 Financial Conduct Authority (FCA) report, approximately 15% of UK adults reported having investments in stocks and shares.