TORONTO -- Major North American indexes continued to plunge Thursday as news of large-scale cancellations failed to ease investors' concerns about the spread of the novel coronavirus pandemic.

"This is an unprecedented fall," said Allan Small, senior investment adviser at HollisWealth, who has been working in the investment world for almost 25 years.

"I have never seen the velocity of this fall as steep or quick as it is."

The S&P/TSX composite index plummeted 1,761.64 points, or 12.34 per cent, to 12,508.45 with every sector in the red and just above a daily low of 12,451.12 points.

In New York, the Dow Jones industrial average dropped 2,352.60 points, or 9.99 per cent, to 21,200.62. That's the worst day for the index since a nearly 23 per cent drop on Oct. 19, 1987.

The S&P 500 index shed 260.74 points, or 9.51 per cent, to 2,480.64. That's a total drop of 26.7 per cent from its all-time high set just last month, well past the threshold for a bear market. It snaps an unprecedented nearly 11-year bull-market run.

The Nasdaq composite fell by 750.25 points, or 9.43 per cent, to 7,201.80.

The collapse in Toronto and on U.S. markets at the start of trading was large enough to trip circuit breakers that forced a pause in trading.

Stock markets had been under pressure in recent weeks amid concerns about the spread of COVID-19, however losses picked up this week after Saudi Arabia moved to boost oil production in a price war with Russia.

European markets did not fare well either. They lost 12 per cent in one of their worst days ever.

The market is trying to determine how much companies are worth, said Small.

"It doesn't know because we don't know how long this virus will linger and how long it will have an impact on business," he said.

On Wednesday, investors hoped U.S. President Donald Trump "would give us something to hang out hats on," but his prime-time address disappointed Wall Street, said Small.

Trump announced travel restrictions on Europe that aim to limit the virus from spreading and hinted at plans for tax cuts and other economic relief, but did not provide details.

Small said investors need to hear that the government is here to help and no business will be left behind during the outbreak.

Even gold, normally considered a safe haven for investors during tumultuous times, plummeted. The April gold contract declined by US$52.00 to US$1,590.30 an ounce.

For individual investors watching the balance of their RRSPs, TFSAs or other accounts dwindle, Small said: "take a deep breath."

For those who can't stand the dramatic drops, he said, there is the option to pull their money out of the market. Though, he cautioned, he believes that would be a mistake.

The other choice, Small said, is to stay in the market, avoid looking at their portfolio for several weeks and wait for a rebound.

He notes these choices do depend on each investor's investment horizon and other factors.

The only positive today, said Small, is that there is no positive.

"The positive could be maybe we're finally at a bottom. I don't know if it's exactly today, but maybe it's somewhere around here."

The Canadian dollar traded for 72.36 cents US compared with an average of 72.75 cents US on Wednesday.

Elsewhere in commodities, the April crude contract fell US$1.48 to US$31.50 per barrel and the April natural gas contract shed 3.7 cents to US$1.841 per mmBTU. The May copper contract dropped by nearly 3 cents to roughly US$2.47 a pound.

This report by The Canadian Press was first published March 12, 2020.

-- With files from The Associated Press