Microsoft’s $440 billion wipeout, and investors angry about OpenAI’s debt, explained

Wall Street’s years-long bet on AI is facing a severe test on Thursday, as investors might begin to view OpenAI–and generative AI in general—not as a catalyst for continuous growth, but as a source of systemic risk for Big Tech.

A sharp selloff in tech stocks on Thursday underscored investors’ exhaustion with the “spend now, profit later” model that has propelled the AI bull market for three years. Microsoft led the retreat, with its shares plummeting 12% by noon, erasing more than $440 billion in market value...