Microsoft's Market Cap Soars by $450 Billion in One Day, Setting a New Record

July 31st, according to BIT (bit.com) market data, Microsoft's stock surged 15.5% at Thursday's U.S. market close, marking the company's fourth-largest one-day gain in history and the largest single-day market cap gain for a U.S. stock.

Investors welcomed its strong earnings report, breaking the recent market sentiment of widespread decline among AI-related companies. The stock's year-to-date cumulative loss narrowed from about 19.3% at Wednesday's close to 5.8%. Data analysis shows that this surge boosted Microsoft's market cap by $450 billion, surpassing Nvidia's $440 billion single-day gain on April 9, 2025, becoming the largest market cap gain in U.S. stock history.