Technology companies reporting yesterday offered disappointing financial results, causing the blue chip Dow Jones Industrial Average to tumble.
IBM and United Technologies reported disappointing quarterly results, sending their shares tumbling.
IBM is the second-highest-weighted component in the Dow and United Technologies is the 10th.
Microsoft announced a net loss of $US3.19 billion ($NZ4.81 billion) in the three months ended June, blaming a hefty writedown on the smartphone business it acquired from Nokia.
Earlier this month, the United States technology giant announced a $US7.5 billion charge to write down the value of the smartphone operations acquired last year from the Finnish group.
Microsoft also took restructuring charges of nearly $US1 billion as part of the move, including job cuts of about 7800 worldwide.
Company revenue fell 5% from a year ago to $US22.2 billion in the quarter.
Sales from Windows, the core of the Microsoft business, fell 22% as the company ramped up the release of the new Windows 10 operating system, aimed at both personal computers and mobile devices.
Yahoo confirmed it had swung to a loss in the second quarter but that revenues grew as the internet pioneer refocused its efforts on mobile and other growing sectors.
The loss of $US22 million compared with a profit of $US270 million in the same period a year ago.
But chief executive Marissa Mayer said she was pleased with the revenue growth, saying: ''Yahoo's transformation continues to make great progress''.
Total revenues jumped nearly 15% to $US1.24 billion, led by what Mayer has dubbed the new emerging areas for Yahoo of ''Mavens,'' or mobile, video, native and social.
Yahoo had struggled in recent years since losing its lead in internet search to Google, and has been aiming for new niches under Ms Mayer's leadership.
A key asset for Yahoo is its stake in Chinese online giant Alibaba.
That stake is to be spun off into a separate company later this year.
Apple forecast fourth-quarter revenue below estimates, sending its shares down 8% in after-hours trading, despite reporting strong iPhone sales.
The company forecast revenue or $US49 billion to $US51 billion, missing the analyst averages of $US51.3 billion.
The world's largest publicly traded company by market capitalisation said it had sold 47.5 million iPhones in its third quarter, up 35% from a year ago but down 22% from the 61.2 million sold in the previous quarter.
The company's iPhone 6 and iPhone 6S, which shattered iPhone sales records when they were launched, are already 10 months old.
The company said net income rose to $US10.7 billion, or $US1.85 per share, from $US7.75billion in the previous quarter.
Revenue rose 32.5% to $US49.61billion from a year earlier, beating expectations.
Apple did not release unit sales of the Apple Watch.
It included the results for the smartwatch in a broad category called ''other'', along with items such as Beats headphones and iPod sales.
Revenue in the category rose 49% to $US2.64 billion.
Action camera maker GoPro Inc broke the trend to report better-than-expected quarterly profit and revenue, helped by strong sales in markets outside North America.
GoPro, whose helmet and body-mounted cameras are popular with surfers, skydivers and other adventure sports enthusiasts, has benefited from a focus on markets such as China, Japan and South Korea.
''China is now a top ten revenue-generating country for GoPro,'' the company said in a statement.
GoPro gets more than half of its revenue from markets outside the United States.
GoPro reported net income of $US35 million for the second quarter ended June 30 compared with a loss of $19.8 million a year earlier.
Revenue rose 71.7% to $US419.9 million.
