Itll be nvidia and openai primarily, id have to imagine

Microsoft already had a proven business model and established products and services before the AI boom. If a company goes under it would almost certainly be one focused almost entirely on AI such as Palantir.

Nah, they already converted all their business clients to recurring revenue and are, relatively, not very exposed to the LLM thing. Sure they will have overspent a bit on datacenters and nVidia gear, but they continue to basically have most of global business solidly giving them money continuously to keep Office and Azure.

In terms of longer term tech companies that could be under existential threat, I'd put Supermicro in there. They are a long term fixture in the market that was generally pretty modest and had a bit of a boost from the hyperscalers as 'cloud' took off, but frankly a lot of industry folks were not sure exactly how Supermicro was getting the business results they reported while doing the things they were doing. Then AI bubble pulled them up hard and was a double edged sword as the extra scrutiny seemingly revealed the answer was dubious accounting all along. The finding would have been enough to just destroy their company, except they were 'in' on AI enough to be buoyed above the catastrophe.

A longer stretch, but nVidia might have some struggles. The AI boom has driven their market cap about 5000%. They've largely redefined most of their company to be LLM centric, with other use cases left having to make the most of whatever they do for LLM. How will their stakeholders react to a huge drop from the most important company on earth to a respectable but modest vendor of stuff for graphics? How strong is the appetite for GPU when the visual results aren't really that much more striking than they were 3 generations of hardware back?