The London Stock Exchange was formally established in 1801.
London's securities market has earlier roots. In 1698, John Castaing published prices for stocks and commodities at Jonathan's Coffee-House, an important early source of organized market information. Brokers were later expelled from the Royal Exchange because of disorderly conduct and began meeting in coffee houses.
The formal London Stock Exchange dates to 1801, when rules were created and membership was organized. This distinction explains why sources may mention both 1698 and 1801: 1698 marks the emergence of a recognizable London market, while 1801 marks the creation of the formal exchange.
The exchange eventually moved into purpose-built premises and became a central institution in British finance. In 2007, it merged with Borsa Italiana to form London Stock Exchange Group, a financial-market infrastructure company that later expanded into other data, clearing, and trading businesses.