"Our team took immediate action to diagnose the problem and communicate with all of our participants while determining the cause and impacts. Due to the timing and the nature of the issue, we made the difficult but necessary decision to shut down trading for the rest of the day. TMX is committed to applying the lessons learned from this incident to help us prevent such issues from recurring in the future." About TMX Group (TSX: X ) TMX Group's key subsidiaries operate cash and derivative markets and clearinghouses for multiple asset classes including equities and fixed income. Toronto Stock Exchange, TSX Venture Exchange, TSX Alpha Exchange, The Canadian Depository for Securities, Montréal Exchange, Canadian Derivatives Clearing Corporation, Trayport and other TMX Group companies provide listing markets, trading markets, clearing facilities, depository services, technology solutions, data products and other services to the global financial community.