Market Capitalization

Market capitalization (market cap) is the total market value of all a company's outstanding shares: share price × total shares outstanding. It is the most widely used metric for categorizing companies by size and is a key determinant of a stock's liquidity, volatility profile, and typical catalyst response characteristics.

Market Cap Tiers

Micro-cap: Under $300M. Extremely high volatility, low liquidity, wide bid-ask spreads. Susceptible to manipulation; requires careful risk management.

Small-cap: $300M–$2B. High volatility, moderate liquidity.

Mid-cap: $2B–$10B. Moderate volatility and liquidity. More institutional coverage and analyst following than small-caps.

Large-cap: $10B+. High liquidity, lower volatility, deep analyst coverage.

Market Cap and Event Reactions

Small-cap and micro-cap stocks tend to show larger percentage moves on news because fewer institutional analysts cover them (lower pre-event pricing efficiency), they have lower float (fewer shares available to absorb buying pressure), and their option markets are less efficient at pricing anticipated moves. TradeAI News covers US-listed equities of every size; see Small-Cap Stocks for the liquidity risks.