(Adds details on results, context on industry)
TORONTO, Nov 6(Reuters) - TMX Group Ltd, the operator of Canada's biggest stock exchange, reported weaker-than-expected quarterly profit hurt by lower trading revenue from its BOX options exchange and cash markets.
The Toronto-based company said its net profit attributable to shareholders was C$39.4 million, or 73 Canadian cents per share, compared with a profit of C$19.2 million, or 35 Canadian cents per share, a year earlier.
Excluding one-time items, the company earned 86 Canadian cents per share. On that basis, analysts on average expected TMX to earn 97 Canadian cents a share in the third quarter, according to Thomson Reuters I/B/E/S.
Revenues rose 3 percent to $170.2 million.
TMX has struggled more than most of its global peers because of its reliance on new issues and capital-raising by the cyclical energy and mining sectors, and it recently migrated its trading platform to offer ultra-fast transaction speeds and diversified via small acquisitions and internal moves.
Late last month TMX said it planned to offer a trading option for investors not using speed-based strategies, in what appeared to be a direct response to the threat presented by incoming player Aequitas.
Before the results were released, TMX stock closed at C$53.69, down 0.61 percent. (Reporting by Alastair Sharp and Anjali Rao Koppala; Editing by Diane Craft, Cynthia Osterman and Bernard Orr)