Top Companies by Market Cap

A company's market capitalization is calculated by multiplying its current share price by the total number of shares outstanding. For example, if a company has 10 billion shares outstanding and the stock trades at $200, its market cap is $2 trillion. Market cap reflects what the public market currently believes the entire company is worth, and it changes constantly as share prices move throughout the trading day.

Large-cap companies typically have a market cap above $10 billion, mid-cap companies fall between $2 billion and $10 billion, and small-cap companies are generally under $2 billion. Large-cap stocks are usually more stable and liquid, while small-cap stocks can offer higher growth potential but come with greater volatility and risk. Definitions can vary by region and index provider.

No — market cap only reflects the equity value of a company, meaning what stockholders own. Enterprise value (EV) is a more complete measure that adds the company's debt and subtracts its cash. Enterprise value is used in financial analysis when comparing companies with different capital structures, while market cap is the most widely used quick measure of size and relative ranking.

Market caps fluctuate continuously during trading hours because share prices are determined by supply and demand in real time. Earnings reports, economic data, interest rate changes, news events, and investor sentiment can all cause rapid price movements. A single earnings surprise can add or erase hundreds of billions in market cap within hours.

Market cap is a forward-looking valuation metric based on investor expectations, while revenue and profit are backward-looking measures of what a company has already earned. A high-growth company may have a very large market cap relative to its current revenue because investors expect future earnings to be much larger. Conversely, a profitable but slow-growing company may trade at a lower market cap relative to its earnings.