Microsoft Corporation added nearly $450 billion to its market capitalisation in a single trading session on Thursday, July 30, the largest one-day gain in stock market history, after fourth-quarter earnings showed Azure cloud revenue growing at its fastest pace since early 2022 and the company projected even stronger growth in the quarter ahead, settling an investor debate that had weighed on the stock for much of the year.
Shares closed up more than 15%, their biggest single-day gain since October 2008, lifting Microsoft's market capitalisation to $3.35 trillion and eclipsing Nvidia's previous record of $441 billion added on April 9, 2025, when markets surged after President Trump announced a 90-day tariff pause.
Azure cloud revenue grew 43% in the quarter, the fastest rate since early 2022, a number that exceeded analyst estimates and answered the question that had suppressed Microsoft's stock all year. In its first quarter of fiscal 2027, Microsoft expects Azure to grow 45% on a constant-currency basis, well above the 40.92% analysts had estimated. For a company whose stock had fallen more than 18% from the start of 2026 to the eve of the results, the combination of a strong beat and a stronger-than-expected outlook was enough to compress months of underperformance into a single session's reversal.
Microsoft said its spending plans remain unchanged, with capital expenditure of $50 billion planned for the fiscal first quarter of 2027 and $175 billion for the 2026 calendar year, a commitment to AI infrastructure that had itself been a source of investor anxiety. The results shifted the framing from how much Microsoft is spending to whether those investments are generating returns, and on Thursday the answer appeared to satisfy even the sceptics.
"The key question was whether it could shift the conversation from how much it is spending on AI to what it is earning from those investments, and the results suggested meaningful progress," said Jake Behan, head of capital markets at Direxion. Brian Mulberry, chief market strategist at Zacks Investment Management, said Microsoft struck exactly the tone markets had been waiting to hear, with the key drivers of growth coming from the cloud and AI divisions rather than from legacy software.
Trading volume reached nearly 100 million shares, more than double the company's average daily turnover, as institutional investors who had been underweight repositioned rapidly into a stock that had underperformed its Magnificent Seven peers for most of the year. At least nine brokerages raised their price targets following the results.
The $450 billion added in a single session is a number that requires a moment of stillness to absorb. It exceeds the entire market capitalisation of all but a handful of companies in the world, was created in approximately six and a half hours of trading, and arrived for a company that was already worth more than $2.9 trillion before the market opened. It is the most vivid single data point yet for how much the market is prepared to reward evidence that AI spending is translating into AI revenue, and how severely it has been punishing any suggestion that it might not.
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