Market capitalisation

Also called: Market cap · Topic: Financial Markets, Instruments, Insurance and Pensions · NCERT: Beyond NCERT

Meaning

Market capitalisation (market cap) is the total value the stock market puts on a company today. It equals the current share price multiplied by the number of shares the company has issued and that are held by all its shareholders (shares outstanding).

Market cap = Share price × Number of shares outstanding

It tells us how big a listed company is in the eyes of investors. Indices like the Sensex and Nifty 50, SEBI's large-, mid- and small-cap groups, and the "Buffett indicator" are all built on it.

Explanation

How it works

• Market cap uses the market price of a share. This is the price set every moment in the secondary market (where investors buy and sell existing shares among themselves).
• It is not the money the company raised. It is what all its shares are worth at today's price.
• Worked example: share price ₹500 × 10 crore shares = market cap of ₹5,000 crore.
• Total market cap of an exchange = the market caps of all companies listed on it, added together.

Full market cap vs free-float market cap

• Free float means the shares that are actually available for trading. It leaves out shares held by promoters (the founders or controlling owners) and shares that are locked in (not allowed to be sold for a set period).
• Free-float market cap = Free-float share × Full market cap
• Worked example: in the company above, promoters hold 60%. So the free float is 40%.

• Free-float market cap = 0.40 × ₹5,000 crore = ₹2,000 crore.

• Why indices use free float:

• Suppose a company has a large promoter holding.
• If full market cap were used, this company would move the index far more than its tradable shares justify.
• Free float counts only the shares that ordinary investors can really buy and sell.

Using market cap to build an index

• Index = (Current free-float market cap of index stocks ÷ Base-period free-float market cap) × Base value
• Worked example: base-period market cap = ₹1,000 crore and base value = 100. Today's free-float market cap = ₹8,00,000 crore.

• Index = (8,00,000 ÷ 1,000) × 100 = 80,000.

• A bigger company carries more weight, so its price changes move the index more.

What makes market cap rise or fall

The number of shares rarely changes, so market cap moves mostly with the share price. The price moves because of:

• Company performance: a good outlook pushes the price up. A bad product, a workers' strike or a big loss pulls it down.
• Government policy: new laws and tax rules change the profits investors expect.
• Political instability, wars and economic shocks: fearful investors sell, and prices fall.
• Boom or crash:
• In a stock market boom, the prices of many companies rise together, so total market cap swells.
• In a stock market crash, prices fall steeply together (usually because of panic selling), so market cap shrinks fast.

In India

• SEBI's size bands (companies are ranked by market cap):
• Large-cap = the top 100 companies.
• Mid-cap = companies ranked 101 to 250.

• Small-cap = companies ranked 251 onwards.

• Indices:

• The Sensex (BSE; 30 stocks; base 1978-79 = 100) has been weighted by free-float market cap since 2003.

• The Nifty 50 (NSE; 50 stocks; base 3 November 1995 = 1000) is also weighted by free-float market cap.

• Settlement rules use it too: SEBI's circular of 10 December 2024 widened optional T+0 (same-day) settlement to cover up to the top 500 scrips by market capitalisation [1].

• Stocks were added 100 at a time each month, starting from the bottom 100 of that list [2].

• Market cap-to-GDP ratio ("Buffett indicator"):

• The ratio of BSE market cap to GDP was 136% at the end of December 2024. This was far higher than China (65%) and Brazil (37%) [3].
• India ranked fifth in the world on this ratio [3].
• India's capital markets grew from 144% of GDP (CY2017) to 175% (CY2024) [4].

Don't confuse with

• Free-float market cap: it counts only the shares that can be traded, and leaves out promoter and locked-in shares. It is always equal to or smaller than full market cap. Sensex and Nifty use free-float market cap, not full market cap.
• Capital raised in the primary market: in an IPO, the company gets money when it sells new shares. A rise in market cap in the secondary market gives the company no fresh money. Only investors' holdings become worth more.
• Face value / book value: face value is the fixed value printed on a share. Book value is net worth taken from the company's accounts. Market cap uses the market price, which reflects what investors expect in the future.
• Price-to-earnings (P/E) ratio: P/E = share price ÷ earnings per share. It shows how costly a share is compared with its profits. Market cap shows how big the company is.

Prelims Hooks

• Market cap = share price × number of shares outstanding. Example: ₹500 × 10 crore shares = ₹5,000 crore.
• SEBI size bands: large-cap = top 100; mid-cap = 101-250; small-cap = 251 onwards, all by market cap rank.
• Sensex and Nifty 50 are both weighted by free-float market cap. The Sensex has used free float since 2003.
• Buffett indicator = total market cap ÷ GDP × 100. India's BSE ratio was 136% (December 2024), and India ranked fifth in the world [3].
• Trap: a rise in market cap does not raise fresh capital for the company. Secondary-market trades only move money from one investor to another.
• Trap: free float leaves out promoter and locked-in shares. It is not the same as "all shares held by the public and promoters".

Mains Points

• Wealth effect vs real investment:
• Rising market cap makes households and companies feel richer, and it makes new issues easier to sell.

• But it adds nothing to fixed investment unless companies actually raise and spend new capital. So a high market cap alone is not proof of real growth in the economy.

• Valuation warning signals:

• India's market cap-to-GDP ratio of 136% (December 2024) was well above China and Brazil [3], and capital markets reached 175% of GDP in CY2024 [4].
• This shows deeper financial markets, but it can also mean over-valuation.

• So safety tools like circuit breakers, price bands and SEBI's investor protection matter more, especially for first-time retail investors.

• Free float and market integrity:

• Free-float weighting stops companies with large promoter holdings from moving the index too much.
• A small free float can still make a stock's price easier to push around. This links market cap measurement to SEBI's work on fair price discovery.

Related concepts

• Secondary market
• Depository
• Demat account
• Clearing corporation
• T+1 settlement
• Algorithmic trading
• Circuit breaker
• Sensex
• Nifty 50
• Free float

Read more

• Secondary market: trading infrastructure, indices and valuation