Tech stocks tumbled for the second day in a row as concerns rise over the hundreds of billions of dollars firms are investing in artificial intelligence (AI).

Shares in Intel plummeted by 28% on Friday, while Google owner Alphabet saw its stock price continue to fall another 1.4% after a 12% plunge on Thursday.

Other tech stocks, including Reddit and Amazon also fell, while the Nasdaq index of the largest tech firms listed in the US, ended October with its worst monthly slide since March 2025.

While tech firms are spending big on AI, their earnings are not always meeting analysts' expectations, spooking investors and creating fears of an AI bubble.

Major tech companies have ramped up artificial intelligence spending, with Meta, Alphabet, Oracle, Amazon, and Microsoft committing to spending $800bn between them in 2026.

Alphabet's stock market value fell sharply on Thursday, taking more than $500bn (£374bn) off its market value after it revealed the AI summaries it now provides as the top answer to search queries were affecting its core search advertising revenue.

At the same time, Alphabet expects to spend up to $205bn this year on investments, almost entirely related to AI.

The bigger losses on Friday were elsewhere however, with Intel shedding more than $130bn in value.

The chip maker said it planned to increase spending on AI despite weaker demand for computers, a major source of demand for its micro-processors.

On Thursday, Intel's finance chief David Zinsner said the firm did not expect to bring in more cash than it spent this year and forecast lower-than-expected revenue for its fourth quarter.

"Looking ahead, we see the PC slowdown continuing at least through the first half of next year," he said in the chip maker's third quarter earnings report.

In the earnings call, he said the firm had significantly ramped up investment in equipment in the third quarter and expected that to be "even more significant" in the following three months.