But there’s one clear winner. Microsoft has added $63 billion to its market capitalization since Friday’s close, according to Fortune’s calculations. The company’s stock reached $378 per share in midday trading on Monday, an all-time high. If that price holds by Monday’s market close, Microsoft’s market cap, based on its 7.429 billion shares outstanding, will total $2.82 trillion.

It’s a remarkable turn of events for Microsoft and CEO Satya Nadella, who could easily have been the biggest losers in the affair. Microsoft has pumped $13 billion into the startup and has made OpenAI’s technology a cornerstone of its product lineup, weaving it into everything from Office365 to GitHub.

The Friday statement by OpenAI’s board, firing Altman because “he was not consistently candid in his communications,” was a direct threat to Nadella’s strategy. Indeed, within minutes of the announcement going public on Friday afternoon, Microsoft’s stock took a nearly 2% hit, falling from $373 to $367 per share—representing a notable loss for a company with a market cap approaching $3 trillion. 

“If Microsoft lost Altman he could have gone to Amazon, Google, Apple, or a host of other tech companies craving to get the face of AI globally in their doors,” Wedbush analyst Dan Ives wrote in a note to investors on Monday.

But Nadella’s clutch reaction under pressure, announcing at midnight on Sunday that he had hired Altman and former OpenAI President Greg Brockman to lead a new AI research lab inside Microsoft, was a “World Series of Poker move for the ages,” Ives said.

Or, as Macquarie Equity Research analysts succinctly put it in the title of their note to Microsoft investors: “When you come at the king you best not miss.”

Microsoft will now employ two of OpenAI’s most influential workers and retain its massive stake in the startup. OpenAI, for its part, appointed former Twitch boss Emmett Shear as interim CEO. It is unclear what Microsoft’s new research team will look like, but the hiring was certainly a powermove on Nadella’s part. 

“We look forward to moving quickly to provide them with the resources needed for their success,” Nadella said in the post, suggesting Microsoft might be willing to hire Altman-loyalists who defect from OpenAI. “We look forward to getting to know Emmett Shear and OAI’s new leadership team and working with them,” he added. 

Altman responded on X, “the mission continues.” 

While the stock pop is sure to please Microsoft leadership, it isn’t all sunshine and rainbows ahead. The company is now responsible for building (and fielding costs for) the new AI research organization under Altman and Brockman. And it may still have to pay billions in existing contracts to a fledgling company, as Fortune editor-in-chief Alyson Shontell reported.