The share prices of the biggest tech firms in the US swung up and down as investors considered their immense spending on artificial intelligence (AI).

Facebook's owner Meta, Google's owner Alphabet, Microsoft, and Amazon all reported their business results for the first three months of this year at the same time on Wednesday.

The companies collectively plan to spend more than half of a trillion dollars on AI this year, with Meta and Amazon making mass job cuts to offset these costs.

Meta's shares slumped over 5% in after hours trading, while Microsoft and Amazon were down 2% and 1.6% respectively. Meanwhile, Alphabet share price jumped almost 6%.

Investors in these firms have become increasingly concerned about whether the money being spent will generate returns.

Wednesday's results revealed mixed bag for the companies on that front.

Mark Zuckerberg, Meta's co-founder and chief executive, said in prepared remarks that the company "had a milestone quarter" with users of its apps and a release of a new AI model, but that seemed to be overshadowed by another increase on costs.

Its share price slumped after it said it would be spending even more on AI projects and infrastructure than it anticipated.

The firm said its planned capital expenditure, the metric companies use to detail their spending on projects that have not yet turned into business growth, will increase to as much as $145bn (£108bn), up from a previous maximum of $135bn.

Alphabet's positive performance and specifics around tangible business results from its AI spending saw the stock jump in after hours trading.

The company said its profits rose by 30% and noted that its Google Cloud business grew by 63%, an increase it attributed specifically to an increase in AI usage by companies that buy cloud services.

Sundar Pichai, Google's chief executive, said in prepared remarks: "Our AI investments and full stack approach are lighting up every part of the business."

Microsoft's stock fell by nearly 2% after the company reported its quarterly results.

Although the company beat its revenue expectations with an increase of 16% to $83b, and profits rose 23% to $38 billion its spending on AI has hit its free cash flow. That metric, essentially how much money a company has in its bank account, is important for investors.

Microsoft's cash flow for the quarter came in at $15.8bn, down almost $6bn from a year ago.

Satya Nadella, Microsoft's chief executive, said the company's AI business is growing. He said the annual run rate of its AI business hit $37bn.

Such a metric, however, is a projection of future sales based on a multiple of current sales. The company did not specify the base level sales figure the run-rate was calculated on.

The company's stock is down nearly 11% so far this year, as questions around its spending on AI and its partnership with OpenAI, in which it has invested more than $10bn, have continued.

Amazon's shares fell after it revealed it would make less money next quarter than initially thought, but the results themselves were in line with analyst expectations.

The company notched a 15% year-over-year increase in profits, and that its increasingly important cloud business grew 28%, the biggest jump it has seen in more than four years.

Andy Jassy, Amazon's chief executive, also boasted of Amazon's expanding business of manufacturing its own AI chips. He said the current annual run rate for Amazon's chips is now $20 billion.

Like Microsoft, Amazon did not specify the base level sales figure its chips business run-rate was calculated on.

"We're in the middle of some of the biggest inflections of our lifetime, we're well positioned to lead, and I'm very optimistic about what's ahead for our customers and Amazon," Jassy said in a prepared statement ahead of a call with financial analysts.

Jassy did not say anything specific about the company's spending on AI overall, but it said earlier this year it would spend $200bn on AI in the coming months, an increase from the $125bn it spent in 2025.