Facebook, Amazon, Alphabet - Google's parent company - and now Apple have all been buffeted after reporting either less than stellar revenues or problems ahead.
They all face growing competition, regulations on what they do and questions whether the years of fast growth are coming to an end.
Today, Apple reported its earnings. In a nutshell, it reported record revenues and profits for the fourth consecutive quarter but it forecast impending difficulties. And that sent share prices down, despite some share analysts on Wall Street thinking it would buck the trends.
The last 10 days have seen shares in Facebook and Alphabet suffer 12 percent falls after they reported earnings. Amazon initially fell 21 percent. Today Apple shares fell 5 percent straight after it reported its earnings.
For a few years these companies (and Netflix), known as the FAANGs, have led technology markets higher.
So what is going on with the companies that once seemed untouchable?
For consumers, the bottom line is more expensive iPhones.
For business watchers, the story is one of slowing down revenues in emerging markets like Brazil, India, Russia and Turkey.
The world's most valuable technology company lost close to $US70 billion in its market value after it reported record revenue and profits - the fourth consecutive quarter it has done so - but warned of problems ahead.
Apple has been steadily raising prices on its flagship iPhones while its sales growth slows; in effect, it is aiming for more revenue off flattening sales. It is also focusing on bulking up its services like iCloud and iTunes.
Apple sold 46.9 million iPhones in the fiscal fourth quarter - analysts expected 47.5 million iPhones. But the average selling price was $US793, well above analyst estimates of $US750.78.
Executives said they also would stop giving the number of iPhones, iPads and Mac computers sold in the future, leading to a further drop in the share price, since investors closely follow the figures.
Apple said it was happy with its performance in China - but there are some worries it is being weighed down by the US-China trade war which has disrupted some of its supply lines. It is also being hit by foreign exchange rates.
The giant social media network is facing a pincer movement. Its advertising revenue is slowing down, just as it's had to spend more to combat problems like issues over data and fake news in its feeds.
Executives warned in July that the pace of spending from advertisers, which makes up nearly all its revenue, would decelerate during the second half of the year. Its stock plummeted nearly 35 percent since then, making it the worst performer of its major US tech peers Amazon, Apple, Netflix and Alphabet.
Revenue did increase in its third quarter - up 33 percent. But that is slowing compared to 47 percent in the same period last year.
Shareholders may be stuck with the more pedestrian rate of growth. Facebook's recklessness with customer data coupled with claims of Kremlin-backed meddling in the 2016 US elections are two massive challenges. Many people also partly blame Facebook for the highly charged political climate and unsettling divisiveness coursing through America and beyond.
Chief executive Mark Zuckerberg has pledged to spend to clean up the toxic newsfeed while fighting regulators eager to rein in Facebook's use of members' information. The likely result is a fall in users, as Twitter is experiencing as it kicks off bots and other accounts. The number of daily active users was flat in North America and fell in Europe compared to the prior quarter. Fewer people using the network reduces Facebook's pricing power with advertisers. That's already flowing through to the operating margin which declined to 42 percent from 50 percent in the third quarter last year.
The numbers that Amazon reported last week are still impressive but it is starting to mention the growing competition in online retail in its predictions as other big firms strike back.
The third-quarter results were the second time running that billionaire Jeff Bezos' firm had fallen short of sales targets.
Now that the Seattle-based firm has devoured retail players like Borders, Sears and Toys 'R' Us, it is facing bigger challenges from multinationals who are making substantial investments to compete.
Revenue from Amazon's international business, which brings in 27.5 percent of total sales, was at the heart of the shortfall in results, growth halving to 13.4 percent compared to the previous quarter.
Amazon is expecting the lead up to Christmas to bolster sales but, crucially, not as much as forecasters expected. Amazon has been open about the increasing challenge of competitors like Walmart and Target to its online retail. Major retailers are now deploying strategies to compete with Amazon for holiday sales.
Like Amazon, the Google parent company is starting to face increasing regulation, more scrutiny and in some areas rising competition.
And that is leading investors to worry that they may increasingly produce slow or unpredictable returns.
Last week, Alphabet missed analysts' quarterly revenue estimates for the first time in two years.
The numbers, like most of the big tech companies, remain eye-watering. Overall revenue rose 21 percent to $US33.74b ($NZ51.52b), missing analysts' estimate by about $US310m ($NZ473m).
Google ad sales contributed 86 percent of revenue. Google has posted strong revenue growth for several years as retailers flock to buy product image ads on Google's search engine and commercials on YouTube. But it has been disrupted by the rise of smartphones, where the company splits ad revenue with technology makers like Apple, and smart speakers, where ads do not appear.
Plus it is facing new privacy rules in Europe and increased competition from Amazon. Google has been fined $US7.7b ($NZ11.7b) for antitrust violations in Europe over the last two years, and heightened attention on privacy, security, competition and the rise of artificial intelligence tools has led investors to fret about potentially costly regulatory scrutiny in the United States and elsewhere.
- RNZ / Reuters