TORONTO (Reuters) - TMX Group said on Wednesday that trading had resumed in all shares on the Toronto Stocks Exchange after an unexplained glitch froze trading of companies whose symbols started with the letters M to Z.
The operator of Canada's largest stock exchange said it was still investigating the cause of the technical failure, but that it had ruled out hacking.
The problem, one of the worst trading glitches to hit the TMX in recent years, affected high-volume stocks such as Research In Motion RIM.TO and Sun Life Financial (SLF.TO).
The glitch did not affect all stock trading in Canada.
A spokeswoman for the Investment Industry Regulatory Organization of Canada, the national self-regulator for the country's investment dealers, said the stocks were still being traded by TMX competitors.
An official at Alpha Group confirmed the alternative trading system continued to match trades even while those companies were frozen on the Toronto Stock Exchange.
The outage happened the same day Canada's competition regulator said it has "serious concerns" about a C$3.8 billion ($3.7 billion) proposal by a consortium of Canadian financial services companies to take over TMX Group, a deal that would bring most of the country's financial exchanges under one roof.
Reporting By Jeffrey Hodgson, Jennifer Kwan and Euan Rocha; editing by Peter Galloway