Guide · Foundations
What is market capitalisation?
The short answer
Market capitalisation, or market cap, is the simplest valuation number in the market and one of the most misread. It is just the share price multiplied by the number of shares outstanding, the total market value of a company's equity. That single figure is the basis for the large, mid and small cap tiers, and it shapes how a stock trades: its liquidity, its volatility, and how much is written and known about it. But market cap is not the company's intrinsic worth, it is not its enterprise value, and a high share price does not make a company large. Market cap tells you the market's price tag, not whether that price is right.
This guide takes the number apart. It starts with the one line of arithmetic that defines it and a worked, illustrative example, then draws the boundaries most beginners miss: why market cap is not the cash in the company, not the cost of buying the whole business, and not something the share price sets on its own. From there it shows what market cap genuinely does do, namely define the size tiers and shape liquidity, volatility and coverage, and it separates full market cap from the free float that is actually available to trade. It closes on the misreadings that cost people money, and on how the Indian market uses the number in practice.
The formula: price times shares outstanding
Market cap is defined by one line of arithmetic: market cap = current share price × total shares outstanding. The share price is what one share changes hands for right now. The shares outstanding are the total number of shares the company has issued and that are held by everyone at once, promoters, institutions and the public alike. Multiply the two and you have the total market value of the company's equity, the price the market is collectively putting on every share added together.
Take an illustrative company whose shares trade at ₹500, with 20 crore shares outstanding. Its market cap is 500 multiplied by 20 crore, or ₹10,000 crore. Change the price to ₹600 and the cap becomes ₹12,000 crore. The share count barely moves from day to day, so almost all of the minute-to-minute change in market cap comes from the price. The count itself shifts only on specific corporate events, a fresh issue of shares, a buyback, or a split, and those are the exceptions rather than the daily rule.
What market cap is not
Because the number is so easy to compute, it gets asked to mean far more than it does. Three boundaries matter. Market cap is not the cash or the assets sitting inside the company: it is the market value of the equity, a price set by buyers and sellers, not a tally of what the business owns. It is not the enterprise value either. Enterprise value starts from market cap and then adds the company's debt and subtracts its cash, because whoever buys the whole business inherits the debt and pockets the cash. Two companies with an identical market cap can have very different enterprise values if one is loaded with debt and the other is not.
And market cap is not something the share price sets by itself. Price is only one of the two factors; the share count is the other, and it is the one people forget. A company can carry a large price and a small cap, or a small price and a huge cap, entirely depending on how many shares exist. It is also not the company's intrinsic worth, the value an analyst would estimate from earnings, assets and cash flows. That estimate is a separate exercise, and it can sit well above or well below the market's price tag.
Market cap is the market's price tag on a company's equity. It tells you what the crowd will pay for it today, not what the business is worth, and not what it would cost to buy outright.
| What market cap does tell you | What it does not tell you |
|---|---|
| The market value of the company's equity right now | The company's intrinsic or fair value |
| How large the company is relative to others, its tier | Whether the share is cheap or expensive |
| How the stock is likely to trade: liquidity, volatility, coverage | The cost of buying the whole business, which is enterprise value |
| Its weight in a free-float-weighted index | How much cash or debt sits inside the business |
The size tiers it defines: large, mid and small cap
Market cap's most important official job in India is to sort companies into size tiers. The Securities and Exchange Board of India defines the tiers by ranking every listed company on its average full market capitalisation. The top 100 companies by that rank are large caps, the next 150, ranks 101 to 250, are mid caps, and everything from rank 251 downward is small cap. The Association of Mutual Funds in India (AMFI) publishes the operational list every six months, which is why a company sitting near a boundary can change tier when the list is refreshed.
The tiers are a ranking, not a fixed rupee threshold, which is a subtle but important point. A company is large cap because it is among the 100 biggest, not because it has crossed some absolute number of crores; if the whole market rises, the rupee value at each boundary rises with it. The companion guide on large-cap, mid-cap and small-cap stocks goes deeper into how the bands behave, but the table below captures the shape.
| Tier | SEBI and AMFI rank by full market cap | Typical traits |
|---|---|---|
| Large cap | Top 100 companies | Deeply liquid, widely covered and steadier; the heavyweights that dominate the main indices |
| Mid cap | Ranks 101 to 250 | A faster growing but more volatile middle tier, less liquid and less covered than large caps |
| Small cap | Rank 251 and below | The largest group by count, thinly traded and lightly researched, and typically the most volatile |
Why cap shapes how a stock trades
Size is not just a label; it changes the lived experience of holding or trading a stock. A very large cap company has an enormous quantity of shares changing hands, so it is deeply liquid: you can buy or sell a meaningful amount without moving the price much, and the gap between the buy and sell quote stays thin. It tends to be less volatile, because it takes a great deal of buying or selling to shift so large a base, and it is heavily covered, followed by analysts, reported in the press, and priced on a steady stream of public information.
A small cap sits at the other end of every one of those scales. Fewer shares trade, so liquidity is thin and a modest order can move the price. Volatility runs higher, because a small flow of money is enough to swing it. Coverage is sparse, so less public information exists and the stock can stay mispriced for longer. None of this makes small caps bad or large caps good; it simply means the same news, and the same size of order, lands very differently depending on where a stock sits on the scale. Whether you are trading or investing, the cap tier quietly sets the terms of engagement.
Full market cap versus free float
There are two versions of the number, and the difference matters. Full market cap uses every share outstanding. Free-float market cap counts only the shares that are actually available to trade in the open market, stripping out the blocks that are locked away: promoter and founder holdings, strategic stakes, and any shares under a lock-in. In many Indian companies the promoter group holds a large slice, so the free float can be a good deal smaller than the full cap.
The distinction is not academic. The free float is the part of the company the market can actually buy and sell, so it drives real liquidity, and it is the version that index providers use to weight their indices, which the Indian-context section below returns to. A company can be enormous on full market cap yet carry a modest free float if most of it is held tight, which affects both how much of it trades and how much weight it pulls in an index.
The misreadings that cost people money
The most common and most expensive misreading is treating a low share price as "cheap". A stock at ₹30 is not cheaper than one at ₹3,000 in any meaningful sense; cheapness is about what you pay relative to what you get, earnings, assets, cash flows, not about the number on the price tag. A ₹30 share can be wildly expensive and a ₹3,000 share a bargain, because the price per share is arbitrary: it depends entirely on how many shares the company chose to slice itself into. To judge value you need valuation ratios such as the price to earnings ratio, not the raw price.
The second misreading is thinking a stock split changes what a company is worth. A split multiplies the number of shares and divides the price by the same factor, so the market cap is unchanged the instant it happens: twice as many shares at half the price is the same total value. A split is a re-slicing of the same pie, not a bigger pie. The share price falling by half in a split is not the stock getting cheaper in any real sense, and mistaking that for a bargain is simply the price-not-cap error wearing a different hat.
A low price is not a discount. Penny-priced shares are not "more affordable" in any way that matters: you can own the same rupee value of a ₹3,000 stock by buying fewer shares of it. Chasing low-priced shares because more of them fit your budget is one of the oldest and costliest beginner habits, and it comes straight from confusing the price sticker with size and value. Judge a share by its market cap and its valuation, never by how many of them a fixed sum will buy.
How the Indian market uses the number
Two features of the Indian market turn market cap from a definition into a working tool. First, the big indices are weighted by free-float market cap. The Nifty 50 and the Sensex hold their constituents in proportion to each company's free float, so the largest free floats carry the most weight and a handful of the biggest names can move the whole index. When the index rises or falls, it is really these free-float-weighted heavyweights doing most of the talking, which is worth remembering before reading too much into a single day's index move.
Second, the size classification is refreshed on a schedule. AMFI publishes the ranked list of large, mid and small cap companies twice a year, and mutual funds that are mandated to hold a particular tier must follow that list. A company that climbs into the top 100 becomes large cap for that period, and one that slips out becomes mid cap, which can change which funds are permitted to hold it. So market cap is not a static badge; it is a live ranking that the market re-reads every six months.
The takeaway. Used well, market cap is the first number you reach for and the last you rely on alone: it tells you how big the market thinks a company is, and therefore how the stock is likely to trade, but never whether that price is fair. Pairing the price tag with a real estimate of value, and knowing precisely which questions market cap can and cannot answer, is part of the foundation that the method we teach is built on.
Common Questions
Frequently Asked Questions
How is market capitalisation calculated?
+Market capitalisation is the current share price multiplied by the total number of shares outstanding. If a company trades at 500 rupees and has 20 crore shares, its market cap is 10,000 crore rupees. Because the price moves every second the market is open, the market cap moves with it, while the share count changes only on events such as a new share issue, a buyback or a split. The result is the total market value of the company's equity, the price the market is collectively putting on the whole company at that moment. It is one line of arithmetic, but it is the foundation for how companies are sized and sorted.
What is the difference between market cap and share price?
+Share price is the cost of a single share, while market cap is that price multiplied by every share outstanding, giving the value of the whole company. The two are often confused, but they are not the same thing, because the share count sits between them. A company with a high price and very few shares can be smaller than one with a low price and a great many shares. This is why a low share price does not make a company small and a high one does not make it large. To compare the size of two companies you must look at market cap, never the price alone.
Does a higher share price mean a bigger company?
+No. The share price on its own says nothing about the size of the company, because size depends on the price and the number of shares together. A stock at 3,000 rupees with one crore shares has a market cap of 3,000 crore rupees, while a stock at 30 rupees with 1,000 crore shares has a market cap of 30,000 crore rupees, ten times larger despite the far lower price. The price per share is really just how finely the company has chosen to slice its equity. Only the market cap tells you how big the company actually is.
What are the market cap categories in India?
+The Securities and Exchange Board of India defines the tiers by ranking every listed company on its average full market capitalisation. The top 100 companies are large cap, the next 150, ranks 101 to 250, are mid cap, and everything from rank 251 downward is small cap. The Association of Mutual Funds in India publishes this ranked list every six months, so a company near a boundary can move between tiers when the list is refreshed. Because the tiers are a ranking rather than a fixed rupee threshold, the boundary in rupees rises and falls with the market as a whole.
Is market cap the same as the value of the company?
+Not in the sense most people mean. Market cap is the market value of the company's equity, the price buyers and sellers are putting on its shares right now, not an estimate of what the business is truly worth. It is also not the enterprise value, which starts from market cap and then adds debt and subtracts cash to reflect what it would cost to buy the whole business. Two companies with the same market cap can be worth very different amounts once their debt and cash are counted. Market cap is a price tag set by the market, not a verdict on whether that price is right.
What is free-float market cap?
+Free-float market cap counts only the shares that are actually available to trade in the open market, leaving out promoter holdings, strategic stakes and any shares under a lock-in. In many Indian companies the promoter group holds a large block, so the free float can be considerably smaller than the full market cap. It matters because the free float is the part of the company the market can really buy and sell, so it drives liquidity. It is also the version that most Indian indices, including the Nifty 50 and the Sensex, use to weight their constituents.
Does a stock split change market cap?
+No. A stock split increases the number of shares and reduces the price by the same factor at the same moment, so the total value is unchanged. A two for one split, for example, doubles the shares and halves the price, leaving the market cap exactly where it was. The company is not worth any more or less the instant it splits; it has simply re-sliced the same value into more, smaller pieces. Treating the lower price after a split as a bargain is a version of confusing price with value.
Why does market cap matter for investors?
+Market cap is usually the first filter an investor uses, because it signals how a stock is likely to behave. Larger caps tend to be more liquid, less volatile and more heavily researched, while smaller caps are thinner, more volatile and less covered, so the tier shapes both the risk and the information available. It also determines a stock's weight in the major indices and which mutual fund categories are allowed to hold it. What market cap does not do is tell you whether the price is fair, so it is a starting point for analysis rather than the conclusion. Sound decisions pair it with a real estimate of value.
Where the facts come from
Sources
- The size tiers. The Securities and Exchange Board of India circular on Categorization and Rationalization of Mutual Fund Schemes defines large, mid and small cap by ranking companies on full market capitalisation, the top 100 as large cap, 101 to 250 as mid cap, and 251 onward as small cap. sebi.gov.in
- The operational list. The Association of Mutual Funds in India publishes the half-yearly list of stocks classified as large, mid and small cap by average full market capitalisation, the reference funds use to place each company in a tier. amfiindia.com
- Free-float index weighting. NSE Indices sets out the methodology for equity indices such as the Nifty 50, in which constituents are weighted by free-float market capitalisation rather than full market cap. niftyindices.com
- Price versus value. Aswath Damodaran, The Little Book of Valuation, draws the distinction between the price the market sets, which market cap measures, and the intrinsic value of the underlying business, which must be estimated separately. pages.stern.nyu.edu
- Illustrative figures only. The rupee prices, share counts and proportions in this guide are illustrative and are meant to show how market cap is calculated and read, not to describe any specific company or a current specification.
Educational note. This guide explains what market capitalisation is and how it is used. It is not a recommendation to buy or sell any security, it makes no claim about returns, and it is not investment advice. Bharath Shiksha is an educational publisher, not a SEBI-registered investment adviser or research analyst.