The US stock market in 2025 is experiencing a level of volatility that is both historic and unsettling. So far this year, there have been 119 trading sessions where an individual American company's market capitalization changed by more than $100 billion in a single day. In 2024, there were 42 such cases for the entire year. Five years ago, in 2020, there were fewer than 10.
This surge is being driven by the enormous scale of mega-cap technology companies. Nvidia, Microsoft, Apple, Amazon, and Alphabet now each command valuations above $2.5 trillion, with Nvidia recently exceeding $5 trillion. Because of that size, a move of just 3% in share price can create or erase over $150 billion in value instantly.
