Tuesday wasn't a good day for International Business Machines. But the company's warning on second-quarter earnings, which cost it about a quarter of its market value, may also ring a bigger alarm about the state of the AI market.

IBM blamed its trouble mainly on a capital-spending shift among customers away from its mainframe computers and related software. Customers, IBM said, were redirecting money to servers, storage and memory that is in short supply.

In other words, IBM's customers-mainly big corporations with sprawling computing setups-aren't spending as much on standard-issue computing. Instead, they're chasing AI.

That big companies are going bananas for AI is no surprise, of course. But IBM's warning also suggested that their AI spending is stretching those customers so thin that they're having to pull back elsewhere.

It's possible that will prove temporary. Many companies for instance believe they need to secure supplies of memory that's in short supply before prices go up further. But it may also indicate that corporate America is starting to run out of runway for AI spending-and that companies are going to have to make more sacrifices down the road to keep the splurge going. That would be a concern for investors far beyond just IBM shareholders.