Meta shares plunged on Wednesday as investors baulked at its promise to maintain spending on artificial intelligence (AI) projects even as profits dwindle.

Shares in the firm behind Instagram and Facebook fell 11% after its results for the quarter from April to June showed revenue grew 28% from a year ago to $61bn (£45.6bn), while profits fell 14% to $6bn.

Meta said it would spend $130bn to $145bn this year, mostly on AI projects, up from the $125bn it said it planned to spend just three months ago.

Chief executive Mark Zuckerberg said the company's AI spending was "accelerating every part of our core business" and that it planned to start selling the technology to other businesses.

Susan Li, Meta's chief financial officer, told financial analysts that selling its tech to other companies would help it drive returns on its AI spending.

"By 2028, we'll have turned over a lot of cards," she said.

Such lines of business have not yet materialized. Meta's free cash flow for the quarter, what it held onto after paying for its operations, was $784m, the lowest level of the metric it has posted in at least five years, according to its financial records.

"What it generated in cash this quarter almost all got eaten by AI infrastructure spending", analyst Mike Proulx at Forrester said. "Investors now have to decide whether Meta's growing list of AI initiatives represents company diversification or distraction."

"There's a bit of similarity to Meta's metaverse missteps in that Meta is once again spending ahead of proven product demand," Proulx added, referring to Meta's previous spending of tens of billions of dollars on virtual experiences that fell flat with users.

Google last week also reported its lowest ever amount of leftover cash, which sent its own stock tumbling.

"I get that this is a big bet across the industry," Zuckerberg said of AI spending. "My personal bet is that the people who invest in this will feel very good and be rewarded over time."

He said on the call that Meta's AI abilities and models were driving engagement on Instagram and Facebook and boosting the ability of smaller businesses to create advertising. Zuckerberg added that the company was developing AI agents, or AI chatbots that act somewhat autonomously.

Such agents "will be the next wave of our product line in the months and years to come," Zuckerberg said.

"Soon, we'll have agents that can work 24/7 on your behalf", Zuckerberg added during the call. "Great personal agents need to just work out of the box. I'm very excited about this and we will have more to share soon."

"We're the best company in the world at scaling experiences to billions of people," he added.

As for Meta's plans to sell AI models and computer tools to other firms for the first time, Zuckerberg said the first step is to make its Muse Spark AI model "easier for companies to integrate".

"We expect to build a large business for large businesses," Zuckerberg said. "We have more coding and product tools on our roadmap."

Although Zuckerberg said the move would flex "a different muscle than we've historically had", he said the financial opportunity was too big to ignore.

"It's not just about selling compute; it's the API services and the productivity services and I think there is a very, very large opportunity there and we're quite focused on that."

Microsoft also reported its quarterly and full year results on Wednesday and it bucked a trend of declining tech stocks, with shares rising 5% in after hours trading.

It's positive reception by Wall Street showed that even huge AI spending can be acceptable to investors when it is not consistently coupled with a lack of clear financial returns.

Sales at Microsoft for the three months from April to June were up 18% to $90bn, with profits up 31% to $36bn and.

Microsoft is also one of the largest investors in OpenAI, and chief executive Satya Nadella used a call with analysts to address the AI company's recent issues with its models improperly breaching the technical operations of other companies.

"The biggest thing you take away from that is you can't depend on any one model," Nadella said.

Microsoft's chief financial officer Amy Hood said its capital spending for the whole of the next year would be $175bn, mostly related to AI and AI infrastructure. That's less than the $190bn it spent in the year to June.