For most companies this was a year of turmoil. For Big Tech it was business as usual, only at accelerated speed. Stock market investors decided the US tech sector was among the year’s big winners, bidding it up by 42 per cent.

Yet, with hindsight, 2020 may come to be seen as the year in which the biggest tech companies slipped from success into excess, leading to a global backlash. There is certain to be increasing pushback from a chorus of critics over the next year as competitors, regulators, politicians, civil-rights organisations and even employees look to curb excessive power.

Big Tech faces three big questions in 2021.

Will investors continue their love affair with technology? Globally, there are good reasons to believe they will. No matter how quickly vaccinations prove effective in slowing the Covid-19 pandemic, the world will continue to move from offline to online. Tech companies are the most immediate and obvious beneficiaries of the trend.

Comparisons are often made between the surge in share prices this year with the mania and crash of 2000. There is undeniably a lot of froth in the market and some extreme valuations. At around $640bn, Tesla is now worth about the same as the next six biggest publicly quoted car companies combined. At around $90bn, Airbnb is worth about one-third as much as the 25 largest quoted hotel chains. Such companies still have a lot to prove.

But, unlike in 2000, many of the more established tech companies are dominant global businesses and look to be solid bets on many financial metrics. Apple, Amazon, Microsoft, Google and Facebook have all become giant companies with highly lucrative franchises in their chosen sectors. Their fate will largely depend on the second question.

How fierce will the regulatory backlash be? In 2020, regulators finally woke up to the dominance of the tech sector and decided to act. US, EU, Indian and UK regulatory authorities all put the squeeze on Big Tech in different ways. Incoming American president Joe Biden is likely to be more activist, too.

But the force of these actions is only likely to be felt in years. In the meantime, the place to watch is China, where regulators are currently taking lumps out of Jack Ma’s business empire. In October, Beijing halted the $37bn listing of Ant Group, the digital financial services company in which Mr Ma is a major shareholder. Earlier this month, regulators launched an antitrust investigation into Alibaba, the digital marketplace he founded.

The big unknown is whether Beijing is just cutting one troublesome tech tycoon down to size (following the playbook of Russia’s Vladimir Putin for dealing with overmighty oligarchs) or whether these latest moves signify a broader attempt by President Xi Jinping to exercise more control over the sector. The latter would clearly have massive implications for the direction and vitality of China’s economy.

“You can either have absolute control or you can have a dynamic, innovative economy. But it’s doubtful you can have both,” Fred Hu, an Ant board member and founder of Primavera Capital Group, told the New York Times.

Given all this, how innovative can Big Tech companies remain? On one level, it seems absurd even to pose the question. These companies boast mountains of cash, vast pools of data and dizzying ambitions to remake industries such as healthcare, finance and cars.

But no matter how strong their advantages, technology remains a people business. Stratospheric house prices and a more hostile visa regime are deterring many overseas workers from moving to Silicon Valley. Indeed, many existing residents are moving out, a trend labelled The Techodus by The Information news website.

Moreover, the Silicon Valley start-up model has gone both national and global. According to a forthcoming report from Mosaic Ventures, even Europe now boasts more than 120 unicorns (tech companies worth more than $1bn) with a collective value of about $600bn. The world’s most driven entrepreneurs may well see promising opportunities closer to home.

As Big Tech executives themselves privately admit, their companies will only prosper to the extent that they can attract and retain the best engineers. At some companies, that looks increasingly in doubt. Google has been repeatedly roiled by employee protests, most recently over the departure of Timnit Gebru, an ethics researcher. An internal Facebook poll in October showed that only 51 per cent of its employees thought the company had a positive impact on the world.

The best indicator of the resilience of Big Tech may be to follow the people, not the money. Watch how the insiders vote with their feet.