Wall St flat as investors focus on trade, await data

The S&P 500 closed slightly higher after flitting between gains and losses during a lacklustre session as investors waited for the next batch of economic data after a robust start to the week spurred by soft inflation data and a US-China tariff truce.

Investors were watching out for more trade developments while President Donald Trump toured the Gulf states and secured $US600 billion ($A929 billion) in commitments from Saudi Arabia. Some US tech companies rallied after the administration announced artificial-intelligence-related deals in the Middle East on Tuesday.

"There's overhanging uncertainty about what world leaders, including President Trump are going to say about trade," said Tim Ghriskey, senior portfolio strategist at Ingalls & Snyder in New York, noting that while earlier tariff policies were on pause there were no final deals in place.

"The recent announcements have been good and that caused a huge rally, but we still have uncertainty," he said.

US stocks had rallied sharply on Monday and advanced again on Tuesday after the United States and China hit pause for 90 days on their fierce tariff dispute.

And it had also helped that data released on Tuesday showed US consumer prices rebounded moderately in April.

Prior to this week, the US announcement of a 90-day tariff pause on April 9 for countries other than China and a limited US-UK trade agreement last week had also helped equities.

US Federal Reserve Vice Chair Philip Jefferson said on Wednesday that while recent inflation data pointed to progress towards the Fed's two per cent inflation goal, the outlook was now uncertain. Chicago Fed President Austan Goolsbee said the data did not necessarily reflect the impact of rising tariffs.

Fed Chair Jerome Powell is slated to speak on Thursday, and his comments will be closely watched for clues on how the central bank plans to proceed with monetary policy easing.

The Dow Jones Industrial Average fell 89.37 points, or 0.21 per cent, to 42,051.06 and its biggest losers were drug companies Merck & Co, down four per cent, and Amgen, which finished down three per cent.

The S&P 500 gained 6.03 points, or 0.10 per cent, to 5,892.58. This added slightly to its year-to-date gain after closing higher for the year on Tuesday for the first time since February 28. The benchmark is still about four per cent below its Feb. 19 record closing high, for its sixth straight day of gains.

The Nasdaq Composite gained 136.72 points, or 0.72 per cent, to 19,146.81.

Eight of the S&P 500's 11 major industry sectors closed lower with Healthcare, down 2.31 per cent, and materials , down 0.96 per cent, the weakest of the bunch.

The biggest gainers were communications services, up 1.6 per cent, and technology, which added about 0.96 per cent.

With Wednesday being a relatively quiet day for economic data, Andrew Graham, managing partner and founder of Jackson Square Capital, said investors were holding steady before April's Producer Price Index (PPI) and retail sales readings due on Thursday morning.

"People are looking for any sort of evidence that the tariff situation has leaked into the real economy," said Graham, but with 90-day pauses to tariff policies in place, he said he is less concerned about April's data readings.

Megacap and growth stocks rose, with Nvidia the biggest S&P 500 boost, rising more than four per cent. Chip designer Advanced Micro Devices shares rose 4.7 per cent after it approved a $US6 billion ($A9.3 billion) share buyback program.

Boeing shares rose 0.6 per cent after state carrier Qatar Airways signed a deal to purchase jets from the US planemaker during Trump's visit to Doha.

In individual stocks, American Eagle Outfitters shares sank 6.4 per cent after the apparel company withdrew its annual forecasts, citing tariff-fueled economic uncertainty.

Declining issues outnumbered advancers by a 1.97-to-1 ratio on the NYSE where there were 132 new highs and 68 new lows.

On the Nasdaq, 1,612 stocks rose and 2,807 fell as declining issues outnumbered advancers by a 1.74-to-1 ratio. The S&P 500 posted 3 new 52-week highs and 9 new lows while the Nasdaq Composite recorded 59 new highs and 104 new lows.

On US exchanges 19.73 billion shares changed hands compared with the 16.77 billion average for the last 20 sessions.