NEW YORK: US stocks plunged around 4 per cent on Thursday in another dramatic session, confirming a correction that has thrown the market's nearly nine-year bull run off course.

The bottom of this recent slide remained elusive for investors, who have been whipsawed this week by huge swings that have shaken a market that had only climbed steadily for months.

With Thursday's drops, the benchmark S&P 500 and the Dow industrials confirmed they were in correction territory, both falling more than 10 per cent from Jan 26 record highs. The S&P 500 slumped 3.8 per cent on Thursday, while the Dow dropped 4.2 percent as losses accelerated late in the trading day.

The Dow Jones Industrial Average fell 1,032.89 points, or 4.15 per cent, to 23,860.46, the S&P 500 lost 100.66 points, or 3.75 per cent, to 2,581 and the Nasdaq Composite dropped 274.83 points, or 3.9 per cent, to 6,777.16.

The S&P 500 last confirmed a correction in Jan 2016, when it fell 13.3 per cent amid concerns about a slump in oil prices.

The S&P closed below the intraday low it had hit on Tuesday, a key level traders had been watching.

Thursday marked another day of recent sharp swings including the S&P 500's biggest drop in more than six years on Monday that pulled equities away from record highs.

"The dust hasn't settled yet, and I think both buyers and sellers are trying to figure out what this market really wants to do," said Jonathan Corpina, senior managing partner for Meridian Equity Partners in New York.

"I would think that this continues to happen for the next few trading sessions for everything to kind of get flushed out."

The retreat in equities had been long awaited by investors as the market climbed to record high after record high with few bumps. The S&P correction is the fifth of this bull market, according to Yardeni Research. The last bear market was during the 2008 financial crisis. - Reuters