In 1972 the Exchange moved to a new purpose-built building and trading floor in Threadneedle Street. Deregulation, sometimes known as "big bang", came in 1986 and external ownership of member firms was allowed for the first time. In 1995 the Alternative Investment Market was launched and in 2004 the Exchange moved again, this time to Paternoster Square.
Between April and May 2006, having been rebuffed in an informal approach, Nasdaq built up a 23% stake in the Exchange. The stake grew to 29% as a result of the London exchange's share consolidation. Nasdaq has since sold its investment.
In 2007 the Exchange acquired the Milan-based Borsa Italiana for 1.6bn euro (£1.1bn; $2bn) to form the London Stock Exchange Group plc. The combination was intended to diversify the LSE's product offering and customer base. The all-share deal diluted the stakes of existing LSE shareholders, with Borsa Italiana shareholders receiving new shares representing 28 per cent of the enlarged register.
On 16 September 2009, the London Stock Exchange Group agreed to acquire Millennium Information Technologies, Ltd., a Sri Lankan-based software company specialising in trading systems, for US$30m (£18m). The acquisition was completed on 19 October 2009.