I have had a theory for a loooong time that Ai is causing a massive stock bubble, especially in the tech space. Microsoft finally realising how much of an oopsie they made with ai could cause a domino effect.
I actual doubt it as a cause, more so justification on wanting to valuation just keep growing to infinity. If not for AI it would be something else. With Nvidia it is cause, but with rest I think it is just general tendency of market wanting to see line going up with any excuse.