Thursday was another volatile day on Wall Street, and the markets finished sharply lower in a tumultuous trading session. The Dow Jones Industrial Average (^DJI +0.72%), S&P 500 (^GSPC +0.22%), and Nasdaq Composite (^IXIC +0.20%) sank between 3% and 4% following news that the state of California had declared a state of emergency in response to its first death from the coronavirus outbreak.

Today's stock market

Data source: Yahoo! Finance.

Among companies making headlines, Zoom Video Communications (ZM +0.96%) was a rare winner in today's session, as the video-conferencing specialist announced strong earnings results. Meanwhile, Boeing (BA +0.85%) wasn't as lucky, as new moves from airlines to try to cut costs and make it through what could be an extremely challenging time ahead had implications for the aircraft manufacturer, as well.

Zoom makes a connection

Shares of Zoom Video Communications finished higher by nearly 7%. The maker of workplace collaboration software and equipment had a lot of good things to say about the growth of its business, and with people less inclined to travel for in-person meetings, Zoom appears to be one of the most obvious beneficiaries of the COVID-19 outbreak.

Image source: Zoom Video Communications.

Zoom's growth in the fourth quarter was phenomenal. The company reported a 78% rise in revenue during the quarter, compared to the prior-year period, capping a year in which Zoom posted 88% top-line growth. That success fell down to the bottom line, as well, with adjusted net income more than quadrupling year over year during the fourth quarter.

Zoom continued to bring on impressive numbers of new customers. Zoom's client count at the end of the quarter came to 81,900, up more than 60% from where it was 12 months ago. Of that number, 641 customers contributed more than $100,000 in revenue over the past year, up 86% from year-ago levels. Net dollar-expansion rates came in above 130% for the seventh quarter in a row.

Zoom sees the good times continuing into the coming fiscal year, with revenue growth of at least 45%. If the coronavirus outbreak accelerates the move toward video conferencing, then Zoom could see even faster sales gains.

Boeing flies lower

Shares of Boeing, meanwhile, were down 8% on a tough day for the aerospace and defense giant. The company faced a number of different challenges, all of which could spell trouble in the short run.

Boeing is coming to terms with the possibility that demand for its aircraft could weaken in the near future. Already, airlines are cutting back on their flight schedules in response to lighter passenger demand, and that could lead cost-conscious executives to delay or cancel orders to Boeing to save money. That means that even if Boeing gets approval for its 737 MAX aircraft to fly again, airline customers might not be in a hurry to take delivery of the backlogged jets.

At the same time, Boeing also faced direct impacts from the coronavirus outbreak, as it sent some employees home from its Everett 777 production facility as a precautionary measure. One employee fell ill, and Boeing followed by sending those working closely with the sick worker home and doing a cleanup of the surrounding work area.

The coronavirus outbreak is just the latest challenge that Boeing is dealing with, and shareholders seem increasingly nervous about the company's ability to weather all of the factors holding it back. Investors have to hope that Boeing will catch a break on at least one front for its stock to regain some of the ground it's lost over the past year.