Wall Street Becalmed By Fretful Investors

US markets have closed flat, with investors worried by slowing momentum in US-China trade negotiations and the UK's Brexit vote.

The Dow Jones was barely changed at 25,709. The S&P 500 dipped a fraction to 2,808, while the Nasdaq lost 0.2 percent to 7,630.

Shares in aviation giant Boeing continued to slide, a day after the US became the last major country to ground the company's top-selling 737 Max aircraft following Sunday's deadly crash in Ethiopia.

Boeing shares were down 1 percent at the close, and have lost about 12 percent this week.

President Donald Trump on Wednesday said trade talks with China were "moving along very well", however the chances both sides will seal grand bargain this month seem to be slipping.

No date has yet been set for the "signing summit" Trump earlier said was likely to occur at the end of this month.

Peter Cardillo of Spartan Capital markets were in a "wait-and-see mode". "The trade deal seems to be pushed back, it caused some hesitancy," he said.

Apple shares added 1.1 percent, continuing gains on the back of a recent analyst upgrade.

Embattled engineering giant General Electric announced it expected negative cash flow of as much as US$2 billion from its core industrial segment this year, leading to more profit reductions. That news however drove its stock up 2.8 percent.

Drug maker Johnson & Johnson fell 1 percent a day after a California jury became the latest to award millions in damages to plaintiff who said the company's baby powder had given her terminal cancer.

Facebook dropped 1.9 percent following a New York Times report that its data deals with major technology companies were under criminal investigation. (AFP)