Trading on the Toronto Stock Exchange and the TSX Venture Exchange resumed as normal at 9:30 a.m. ET on Thursday, a day after a technical problem resulted in a near day-long shutdown.

While early trades went through on Wednesday, a problem was confirmed about seven minutes into the day with the data feeds that provide quotes. Trading was stopped Wednesday at 9:48 a.m. ET. During the 18-minute session, approximately 28,000 trades occurred.

The glitch left TMX Group, the owner of the two exchanges, scrambling to explain and fix the problem.

TMX said all data feeds were restored at 3:41 p.m. Wednesday, but not before the trading session was cancelled.

The market owner said a "network firmware issue" resulted in complications with data sequencing, which affected quotes going out. A backup system also failed.

On Thursday, the chief executive officer of TMX Group apologized for the gaffe.

"Yes, we had an issue yesterday," said Tom Kloet. "I'm not ducking that in any way.

"We think that we've addressed it in the right way, and I'm very confident that our systems are prepared for the kinds of activities the Canadian capital markets should expect, maybe even beyond that, " he told CBC News.

While investors could trade again, they were not in a positive mood. The S&P/TSX composite index finished down 298.76 point, or 3.4 per cent, closing at 8,425.35. The decline was led by a loss of 7.8 per cent for the gold sub-group, a 7.2 per cent drop in the energy sector, and a slide of 6.5 per cent for the mining group.

TMX shares traded down 39 cents at $24.21.