NEW YORK (AFP) - Strong gains by some tech giants helped US stocks mostly rise on Wednesday (Nov 21) after a two-day rout left the Dow and S&P 500 in the red for 2018.

The tech-rich Nasdaq Composite Index was the biggest mover, jumping 0.9 per cent to 6,972.25, thanks to gains by beaten-down giants like Amazon and Facebook.

But the Dow Jones Industrial Average finished essentially flat at 24,464.69 after fading badly in the last hour of trading. The broad-based S&P added 0.3 per cent at 2,649.93, ending well below its session peak.

Tom Cahill of Ventura Wealth Management said tech companies had already began to turn on Tuesday.

"The move continued on Wednesday," he said. "It shows that some portfolio managers are looking for bargains."

Even with Wednesday's better performance, major US indices were still off significantly for the week following back-to-back routs that were attributed to worries about the US-China trade war and higher Federal Reserve interest rates.

Among data releases on Wednesday, orders for US durable goods fell an unexpectedly big 4.4 per cent to US$248.5 billion (S$341 billion), according to government data.

But data from the National Association of Realtors showed a rise in existing home sales in October for the first time since March.

Among individual stocks, Dow member Johnson & Johnson dropped 3.1 per cent after a US appeals court refused to block sales of a generic version of its prostate cancer drug Zytiga.

Agricultural equipment manufacturer Deere & Co rose 2.4 per cent after reporting fourth-quarter earnings of US$2.42 per share, a bit below analyst expectations.

Analysts said the results were better than feared in light of higher costs of steel and other raw materials.