(Bloomberg) -- After last week's wipeout in chips and the broader selloff in technology stocks, pressure is building for the biggest spenders on artificial intelligence to justify their expenditures to beleaguered traders with increasingly itchy fingers hovering over their sell buttons.

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The AI euphoria that drove the stock market to all-time highs just a month ago is clearly waning. Information technology was the worst performing group in the S&P 500 Index last week, which slid 1.6% while the tech-heavy Nasdaq 100 Index lost 4.1%. Chip stocks were the main culprit, with the Philadelphia Stock Exchange Semiconductor Index sinking 10% for its worst week since April 2025.

Even Elon Musk's dream factory SpaceX is taking a hit, plunging 15% last week after dropping 10% the week before, tumbling below its initial public offering price and erasing $1 trillion of market value from its peak.

"Investors are getting to the point where they're uncomfortable with how much money is being spent and they're worried about a bubble," said Jake Seltz, portfolio manager at Allspring Global Investments. "Ultimately, we need to see a re-acceleration in revenue."

With skepticism mounting about the hundreds of billions of dollars being poured into data center development, earnings reports over the next two weeks from the biggest spenders will be scoured for evidence that the investments are generating bigger returns. Tesla Inc. and Alphabet Inc. kick off Big Tech's reporting season on Wednesday. Then Microsoft Corp., Meta Platforms Inc., Apple Inc. and Amazon.com Inc. hit the following week. Together, the six stocks account for a quarter of the market capitalization-weighted S&P 500. Nvidia Corp. reports later next month.

The stakes are high. An index tracking the Magnificent Seven tech giants is lagging the S&P 500 this year, a rarity for the group that has led the market higher for most of the past four years. At the same time, concerns about spending are hitting semiconductor stocks, which have benefited most from the outlays and are leading contributors to the benchmark's 8.9% gain this year.

Most of the focus this week will be on Alphabet. The Google parent is widely seen as an AI winner owing to the popularity of its Gemini chatbot, homegrown data center chips and expansion in its cloud-computing business. But growth in those areas has come at a big cost. Alphabet's capital spending is projected to more than double this year to $187 billion, and like many of its peers it's increasingly turning to debt and equity markets to fund it.