An employee passes a stock board at the Toronto Stock Exchange.
The London Stock Exchange is to buy the owner of the Toronto Stock Exchange in an all-share deal to create a major centre for trading in mining shares if likely political opposition in Canada can be overcome.
LSE shareholders will end up owning 55 per cent of the combined group, the companies said.
Here are some major stock-exchange deals:
July, 2007: Chicago Mercantile Exchange Holdings Inc, the world's largest derivatives exchange, agrees to buy cross-town rival CBOT Holdings Inc for more than $11 billion, ending a century of competition to create the world's largest publicly traded exchange by market capitalization .
April, 2007: NYSE Group Inc acquires Euronext NV, an Amsterdam-based provider of securities brokerage services for around $10.2 billion to create NYSE Euronext .
October, 2010: Singapore Exchange agrees an $8.3 billion takeover of Australia's ASX Ltd to create Asia's fourth-largest stock exchange. Deal awaiting government approval.
August, 2008: CME Group buys NYMEX Holdings Inc, a provider of physical commodities futures and options exchange, in a deal valued at $7.56 billion.
February, 2008: Nasdaq acquires Nordic European-based exchange operator OMX for around $4 billion, forming Nasdaq OMX Group .
December, 2007: Eurex AG acquires U.S.-based International Securities Exchange Holdings Inc, a provider of equity options trading services, for $2.82 billion.
March, 2006: Archipelago Holdings Inc merges with the New York Stock Exchange to form NYSE Group Inc in a stock-swap deal valued at $2.26 billion.
October, 2007: London Stock Exchange buys Borsa Italiana SpA, a Milan-based provider of securities brokerage services, in a $2.15 billion deal.
July, 2006: Australian Stock Exchange Ltd acquires SFE Corp Ltd, a commodities future exchange, in a $1.59 billion deal.
May, 2008: TSX Group Inc acquires Bourse de Montreal Inc for $1.19 billion.
October, 2008: NYSE Euronext buys American Stock Exchange from Amex Membership Corp for $260 million in stock.
March, 2000: Stock Exchange of Hong Kong buys Hong Kong Futures Exchange in a stock swap valued at $160.2 million.