Source: https://mochatrade.com/learn/glossary/market-cap-categories

# Market cap categories (mega/large/mid/small)
URL: https://mochatrade.com/learn/glossary/market-cap-categories
Last modified: 2026-10-17

Market cap categories group US companies by size: mega above $200 billion, large $10 to $200 billion, mid $2 to $10 billion, small $300 million to $2 billion. Size decides [which index holds a company](https://mochatrade.com/learn/us-market-structure/us-stock-market-explained), therefore which passive funds [must buy it](https://mochatrade.com/learn/us-market-structure/who-moves-us-stocks), and smaller caps react hardest to [the Fed](https://mochatrade.com/learn/us-market-structure/how-the-fed-moves-markets).

## Related terms

- US ETF: https://mochatrade.com/learn/glossary/us-etf
- Index ETF: https://mochatrade.com/learn/glossary/index-etf
- Market capitalization: https://mochatrade.com/learn/glossary/market-capitalization
- Index rebalancing: https://mochatrade.com/learn/glossary/index-rebalancing
- US Treasury: https://mochatrade.com/learn/glossary/us-treasury
- Federal Reserve: https://mochatrade.com/learn/glossary/federal-reserve