NEW YORK World stock indices fell on Friday as a global cyber outage rattled investors by disrupting operations across multiple industries, while the dollar climbed along with Treasury yields.

The S&P 500 and Nasdaq registered their biggest weekly percentage declines since April.

The outage hit services from airlines to banks and healthcare.

Cybersecurity firm CrowdStrike fell 11.1% after an update to one of its products appeared to trigger the outage that affected customers using Microsoft's Windows operating system, disrupting businesses across sectors. Microsoft ended down just 0.7%.

The Cboe Volatility index, which is known as Wall Street's 'fear gauge', touched its highest level since late April.

"Today's outages remind us that services can have supply chain disruptions too," said Jeff Kleintop, the chief global investment strategist of Charles Schwab. "While not a cyberattack, the outage is a worrisome reminder of how our systems are deeply integrated."

The Dow Jones Industrial Average fell 377.49 points, or 0.93%, to 40,287.53, the S&P 500 lost 39.59 points, or 0.71%, to 5,505.00, and the Nasdaq Composite lost 144.28 points, or 0.81%, to 17,726.94.

MSCI's gauge of stocks across the globe fell 6.58 points, or 0.80%, to 810.87. The STOXX 600 Index fell 0.77%.

Investors also braced for important results in the US second-quarter earnings season in the upcoming weeks. Results from megacaps will be in focus, with the S&P 500 technology-related sector falling 5.1% this week as investors rotated into sectors that have languished so far in 2024.

Tesla and Google-parent Alphabet both report on Tuesday, kicking off results from the "Magnificent Seven" megacap group of stocks that have propelled markets since early 2023. Microsoft and Apple are set to report the following week.

The dollar index climbed and was on pace for its first weekly gain in three, bouncing back on recent US economic data and concerns about the technology outage.

The dollar index, which measures the greenback against a basket of currencies including the yen and the euro, gained 0.21% to 104.36, with the euro down 0.14% at US$1.0881.

Against the Japanese yen, the dollar strengthened 0.06% to 157.46.

The Federal Reserve is scheduled for its next policy announcement at the end of July.

Markets expect only a slight chance for a cut of at least 25 basis points, while almost completely pricing in a cut in its September meeting, according to CME's FedWatch Tool.

US Treasury yields rose as investors waited for fresh data next week.

The yield on benchmark US 10-year notes rose 5.5 basis points to 4.243%, from 4.188% late on Thursday.

Oil prices fell as investors eyed a possible ceasefire in Gaza. US crude lost US$2.69 to settle at US$80.13 a barrel, while Brent fell US$2.48 to US$82.63.

In cryptocurrencies, bitcoin gained 5.11% to US$67,083.35.

  - Reuters