Microsoft’s stock has biggest one-day gain since 2008, adding $480 billion in market value as cloud business booms

Microsoft stock prices surged as much as 17% on Thursday to above $455, the largest single-day gain in nearly 20 years.

The resurgence followed the tech giant’s 2026 fiscal year fourth-quarter results on Wednesday, which appeared to finally convince investors that CEO Satya Nadella and chief financial officer Amy Hood’s strategy for converting an estimated $190 billion in AI spending this year into rising revenue growth is bearing fruit. 

Microsoft went into earnings this week with its stock down nearly 30% from an October 2025 high of $555, depressed by months of investor funk about ephemeral returns in the AI sector following a massive investment in a build-out now expected to exceed $850 billion across the hyperscalers and cloud providers. The stock closed at $390.54 on Wednesday, and then briefly hit $456 in afternoon trading Thursday, adding about $483 billion in market value during the day. 

The stock’s Thursday rally represents the single biggest one-day gain since 2008, when Microsoft’s stock increased 19%, according to Jefferies.