5 things to know before the stock market opens Friday

U.S. stock futures were lower on Friday as coronavirus headlines keep investors on edge. On Thursday, the Dow Jones Industrial Average swung from a 224-point loss to close up 124 points. Wall Street bounced off the lows after the World Health Organization declared the coronavirus outbreak a global health emergency — but at the same time, did not recommend restricted travel to China. The WHO also said China had the situation under control. Also Friday, Dow component Caterpillar were down slightly in the premarket after the company's CEO warns about "global economic uncertainty." The heavy equipment marker on Friday reported mixed fourth-quarter results. Dow stock Exxon Mobil also issued mixed quarterly results.

While the Dow and S&P 500 were tracking for declines at Wall Street's open on Friday, the Nasdaq was poised to buck the trend and move higher as shares of Amazon were surging 11% in the premarket. The e-commerce and cloud giant on Thursday smashed earnings and revenue expectations for the fourth quarter. Amazon is set to open above a $1 trillion market cap. Amazon first hit a $1 trillion market cap in September 2018 but went below that level after the stock market at the time tanked. Apple, Microsoft and Alphabet are all also above the $1 trillion threshold.

IBM shares jumped as much as 5% in the premarket after the company said cloud chief Arvind Krishna will become its 10th CEO, replacing Ginni Rometty, effective April 6. Rometty, who joined IBM in 1981, will remain executive chairman through the end of the year, when she will retire. During Rometty's tenure as CEO, which began in 2012, shares of IBM fell about 26%, compared with the S&P 500's advance of 160%. Jim Whitehurst, Red Hat's former CEO, is becoming IBM's president. IBM completed its $34 billion Red Hat acquisition in July.

Chinese health officials raised their numbers of confirmed coronavirus cases to over 9,800, with 213 deaths in China. Britain confirmed the first two cases of the coronavirus in the U.K., less than 24 hours after the World Health Organization declared the outbreak a global emergency. The U.S. confirmed its first person-to-person transmission of the virus — the husband of the Chicago woman who brought the infection back from Wuhan, China, the epicenter of the outbreak. The State Department also warned against traveling to China.

The Senate is expected to vote on Friday on whether to call witnesses in the impeachment trial of President Donald Trump. If Democrats can persuade four senators to join them in supporting witnesses, the trial could proceed for weeks or months longer. If the GOP-majority Senate votes against witnesses, then the trial could quickly proceed to a final vote on whether to acquit Trump or remove him from office as soon as next week. Republican Sen. Susan Collins of Maine said Thursday night she will break ranks and vote for witnesses.