The formula and what it represents
Market capitalization (market cap) is Share Price × Shares Outstanding. It is the total dollar value the equity market currently places on a company's outstanding common shares. Because share prices change every trading day, market cap moves continuously — a company's rank in any market-cap leaderboard reflects the latest available close, not a fixed point in time.
Browse the live ranking on top companies by market cap, or see the elite subset on the trillion-dollar club page.
Size buckets — small, mid, large, mega
There is no regulatory definition for "small cap" or "large cap"; the labels are convention. The most widely used U.S. thresholds are:
- Micro cap: under $300 million.
- Small cap: $300 million to $2 billion.
- Mid cap: $2 billion to $10 billion.
- Large cap: $10 billion to $200 billion.
- Mega cap: above $200 billion.
- Trillion-dollar club: above $1,000 billion ($1 trillion).
Index providers (S&P, Russell, MSCI) use slightly different thresholds, often tied to percentile cut-offs of the broad market. The categories are useful as shorthand for liquidity, analyst coverage, and typical volatility — not as a valuation signal.
Full cap vs free-float cap
Full market cap uses every share outstanding, including those locked up by founders, governments, or strategic owners. Free-float market cap counts only the shares actually available to public trading. Major indices (S&P 500, MSCI World) weight constituents by free float rather than full cap, so a company with a single very large insider holder can have meaningfully different rankings depending on which definition is used.
Market cap vs enterprise value
Market cap measures only equity value. Enterprise value (EV) adds net debt — i.e. EV = Market Cap + Debt − Cash. EV is what an acquirer would have to pay to take over the company on a debt-free, cash-free basis. Two companies with identical market caps can have very different EVs. For heavily leveraged businesses (utilities, telecoms, real-estate companies) EV is the more meaningful size measure; for net-cash-rich companies (megacap tech) market cap and EV diverge in the opposite direction.
Market cap is not the only size metric
Market cap reflects how the equity market values future profits. A company can have high market cap and modest current sales (typical for high-growth tech) or huge sales with modest market cap (typical for low-margin distribution businesses). For size by sales, see the revenue ranking; for size by profitability, the earnings ranking. The three rankings rarely produce identical orderings.
Sector slices and related concepts
To see the live market cap of a specific company, open its company hub.