Investors are still betting on AI, but doubts are piling up

Artificial intelligence remains the defining investment theme across public and private markets. Yet the confidence that once made AI the default answer for investors is beginning to face pressure from concerns about value, funding and execution.

AI still drives a large share of market gains

Since 2024, approximately two-thirds of the S&P 500’s returns have come from 42 AI-related stocks, according to the source material. The figures underline how heavily market performance has become linked to a relatively concentrated group of companies associated with the technology.

Private markets are showing a similar concentration. Nearly all venture capital dollars this year are flowing into AI, while some firms are approaching valuations of $1 trillion. That level of investor attention has made AI central to financing activity as well as public-market performance.

Questions are emerging around the investment case

At the Alpha Partners AlphaMarket 2026 conference, discussions with investors reflected concerns that could challenge the sector’s prevailing consensus. The issues include elevated valuations, the availability and terms of financing, the cost of building supporting infrastructure and the pace at which AI is being adopted.

These concerns do not erase the strong flow of capital into AI, but they point to a more demanding environment for companies and investors. Businesses linked to the technology are now being assessed not only on their promise, but also on how financing needs, infrastructure spending and adoption timelines support their valuations.

What comes next

AI continues to command substantial investor interest, but the debate is becoming more focused on the sustainability of that enthusiasm. Valuations, funding, costs and adoption will remain central considerations as the market weighs the technology’s next phase.