It's concerning but to be fair I have felt that way for... I'm not sure, more than the last five years maybe, and the S&P 500 has almost doubled in that time.

The other factor to consider is that to me the valuations don't seem to be driven by retail investors or the sell side (meaning investment banks floating dubious IPOs, if I have the jargon correct).

This seems to be more driven by private and corporate investment in various aspects of the AI sector, while my impression at least is that the public tends to be rather negative about AI.

If the major tech companies and I guess private investors are betting too big on AI, does that really qualify as irrational exuberance? I don't know.

But regardless at some point of valuation it doesn't matter how valuable the technology proves, it will still be overvalued.