Market Capitalization

Market cap is the standard way markets rank companies by size. The formula is straightforward: suppose a company has 500 million shares outstanding and each share trades at $40 — its market cap is $20 billion. That single number lets investors compare a tiny startup with a global corporation without needing to dig into balance sheets. You can see live market-cap rankings on the stocks pages.

Market cap changes every second the market is open, because the share price changes while the share count stays relatively fixed. A company's share count only changes meaningfully when it issues new shares, buys back existing ones, or carries out a stock split. This is why market cap is sometimes called a "real-time vote" on a company's value — the crowd of buyers and sellers is constantly updating it. The same concept applies in crypto markets, where market cap = token price × circulating supply.

A common confusion is treating market cap as the price to buy a company. In practice, attempting to acquire a company typically costs far more than its market cap, because buyers must offer a premium above the current share price to persuade shareholders to sell. Market cap also excludes debt: two companies with identical market caps can have very different total obligations. Enterprise value (market cap plus net debt) is the figure analysts use when they want a fuller picture of a company's total cost.

Market cap tiers — often labeled large-cap, mid-cap, and small-cap — vary by market and are redefined periodically by index compilers. These tiers matter because many funds are restricted to investing only within a certain size range, which affects how liquid different stocks tend to be.