Market Capitalization

Market capitalization, commonly called market cap, is the simplest way to estimate the total value of a publicly traded company. It is calculated by multiplying the current stock price by the total number of outstanding shares. For example, a company with 100 million shares trading at $50 per share has a market cap of $5 billion.

Companies are typically categorized by market cap: mega-cap (over $200 billion), large-cap ($10 to $200 billion), mid-cap ($2 to $10 billion), small-cap ($300 million to $2 billion), and micro-cap (below $300 million). Each category carries different risk and return characteristics. Large-cap stocks tend to be more stable with moderate growth, while small-cap stocks offer higher growth potential but greater volatility.

Market cap is used to weight stocks in major indices. In the S&P 500, companies with larger market caps have a proportionally greater influence on the index's performance. Understanding market cap helps investors build diversified portfolios across company sizes and evaluate whether a stock's valuation is reasonable relative to its earnings, revenue, and growth prospects.