Microsoft shares plunged 19%, marking the software giant's steepest drop since 2000, according to a report by South Korean outlet Chosun Ilbo. The sell-off, the report says, was driven by mounting investor concern over the cost of Microsoft's artificial intelligence buildout.
At the heart of the anxiety is the enormous expense of the infrastructure that powers modern AI — the data centers, specialized chips, and computing capacity needed to train and run large models. Chosun Ilbo frames the plunge as a market reaction to those AI costs, suggesting shareholders are questioning how much the company is spending and how quickly that spending will translate into profit.
A move of this size is notable on its own. A 19% single decline in one of the world's most valuable companies erases a significant amount of market value and can ripple across index funds and retirement portfolios that hold Microsoft as a core position. The comparison to 2000 is also striking: that year sits at the tail end of the dot-com boom, a period remembered for inflated technology valuations that eventually corrected sharply.
The available source does not detail the exact dollar figures behind Microsoft's AI spending, the specific earnings or guidance that may have triggered the drop, or how other technology stocks responded. Those specifics remain unconfirmed here.
Why it matters: the reaction signals that Wall Street's patience with the AI spending race may be thinning, and that even dominant tech companies now face pressure to show the massive bills for AI infrastructure will pay off.