The AI funding machine keeps churning while public markets hit the brakes. Microsoft and Nvidia just committed $15 billion to Anthropic even as their own shares tumbled for a fourth straight day, dragging the S&P 500 to its longest slide since August. It's a tale of two markets - private AI valuations soaring while public tech investors grow increasingly skeptical.
The disconnect couldn't be starker. While Microsoft writes a $5 billion check to Anthropic and Nvidia antes up $10 billion more, public investors are heading for the exits. The S&P 500 just logged its fourth straight red session - the longest losing streak since August - with the very same companies funding AI's future watching their own valuations crumble.
It's become almost formulaic at this point. Company X invests in Company Y, and Company Y commits to buying compute power from Company X. Anthropic will purchase services from both its new backers in what's essentially a $15 billion handshake deal that keeps the money circulating within Big Tech's inner circle.
The timing feels particularly awkward. Google just rolled out Gemini 3.0, with DeepMind CEO Demis Hassabis promising it will trade "cliché and flattery for genuine insight." Yet even as these technical milestones pile up, public market sentiment sours. Nvidia, Amazon, and Microsoft all tumbled Tuesday, dragging tech-heavy indexes down with them.
CFRA's chief investment strategist Sam Stovall calls Nvidia "the top company within the top industry within the top sector" - which makes Wednesday's earnings report a pivotal moment. If the chip giant fails to meet sky-high expectations, this market slide could extend well beyond four days.
The math behind Anthropic's new $350 billion valuation tells the story of private market exuberance. That's more than the market cap of most S&P 500 companies, built on promise rather than proven revenue streams. Meanwhile, established tech giants with actual profits are getting hammered by investors questioning whether AI spending will ever translate to returns.
Bitcoin briefly dipped below $90,000 before recovering, adding crypto weakness to the broader tech selloff. Even Asia-Pacific markets caught the contagion Wednesday morning, with technology stocks dragging indexes lower across the region.











